Standardize header names and file locations

This is both a really big and a really small commit. It is small in
that it only contains renaming, moving and modification of include
directives caused by this.

It is really big in the obvious way of touching something like 200
files.

The new rules for naming files is simple: headers use the `.hpp`
extension. The rules for physical file layout is still kinda in
progress, but the basics are also simple:
 * Significant parts of functionality get their own subfolder
   * Benchmarking is in `catch2/benchmark`
   * Matchers are in `catch2/matchers`
   * Generators are in `catch2/generators`
   * Reporters are in `catch2/reporters`
   * Baseline testing facilities are in `catch2/`
 * Various top level folders also contain `internal` subfolder,
   with files that users probably do not want to include directly,
   at least not until they have to write something like their own
   reporter.
    * The exact files in these subfolders is likely to change later
      on

Note that while some includes were cleaned up in this commit, it
is only the low hanging fruit and further cleanup using automatic
tooling will happen later.

Also note that various include guards, copyright notices and file
headers will also be standardized later, rather than in this commit.

src/catch2/internal/catch_test_case_tracker.hpp

@@ -0,0 +1,160 @@
+/*
+ *  Created by Phil Nash on 23/7/2013
+ *  Copyright 2013 Two Blue Cubes Ltd. All rights reserved.
+ *
+ *  Distributed under the Boost Software License, Version 1.0. (See accompanying
+ *  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+ */
+#ifndef TWOBLUECUBES_CATCH_TEST_CASE_TRACKER_HPP_INCLUDED
+#define TWOBLUECUBES_CATCH_TEST_CASE_TRACKER_HPP_INCLUDED
+
+#include <catch2/internal/catch_compiler_capabilities.hpp>
+#include <catch2/internal/catch_common.hpp>
+
+#include <string>
+#include <vector>
+#include <memory>
+
+namespace Catch {
+namespace TestCaseTracking {
+
+    struct NameAndLocation {
+        std::string name;
+        SourceLineInfo location;
+
+        NameAndLocation( std::string const& _name, SourceLineInfo const& _location );
+    };
+
+    struct ITracker;
+
+    using ITrackerPtr = std::shared_ptr<ITracker>;
+
+    struct ITracker {
+        virtual ~ITracker();
+
+        // static queries
+        virtual NameAndLocation const& nameAndLocation() const = 0;
+
+        // dynamic queries
+        virtual bool isComplete() const = 0; // Successfully completed or failed
+        virtual bool isSuccessfullyCompleted() const = 0;
+        virtual bool isOpen() const = 0; // Started but not complete
+        virtual bool hasChildren() const = 0;
+
+        virtual ITracker& parent() = 0;
+
+        // actions
+        virtual void close() = 0; // Successfully complete
+        virtual void fail() = 0;
+        virtual void markAsNeedingAnotherRun() = 0;
+
+        virtual void addChild( ITrackerPtr const& child ) = 0;
+        virtual ITrackerPtr findChild( NameAndLocation const& nameAndLocation ) = 0;
+        virtual void openChild() = 0;
+
+        // Debug/ checking
+        virtual bool isSectionTracker() const = 0;
+        virtual bool isGeneratorTracker() const = 0;
+    };
+
+    class TrackerContext {
+
+        enum RunState {
+            NotStarted,
+            Executing,
+            CompletedCycle
+        };
+
+        ITrackerPtr m_rootTracker;
+        ITracker* m_currentTracker = nullptr;
+        RunState m_runState = NotStarted;
+
+    public:
+
+        ITracker& startRun();
+        void endRun();
+
+        void startCycle();
+        void completeCycle();
+
+        bool completedCycle() const;
+        ITracker& currentTracker();
+        void setCurrentTracker( ITracker* tracker );
+    };
+
+    class TrackerBase : public ITracker {
+    protected:
+        enum CycleState {
+            NotStarted,
+            Executing,
+            ExecutingChildren,
+            NeedsAnotherRun,
+            CompletedSuccessfully,
+            Failed
+        };
+
+        using Children = std::vector<ITrackerPtr>;
+        NameAndLocation m_nameAndLocation;
+        TrackerContext& m_ctx;
+        ITracker* m_parent;
+        Children m_children;
+        CycleState m_runState = NotStarted;
+
+    public:
+        TrackerBase( NameAndLocation const& nameAndLocation, TrackerContext& ctx, ITracker* parent );
+
+        NameAndLocation const& nameAndLocation() const override;
+        bool isComplete() const override;
+        bool isSuccessfullyCompleted() const override;
+        bool isOpen() const override;
+        bool hasChildren() const override;
+
+
+        void addChild( ITrackerPtr const& child ) override;
+
+        ITrackerPtr findChild( NameAndLocation const& nameAndLocation ) override;
+        ITracker& parent() override;
+
+        void openChild() override;
+
+        bool isSectionTracker() const override;
+        bool isGeneratorTracker() const override;
+
+        void open();
+
+        void close() override;
+        void fail() override;
+        void markAsNeedingAnotherRun() override;
+
+    private:
+        void moveToParent();
+        void moveToThis();
+    };
+
+    class SectionTracker : public TrackerBase {
+        std::vector<std::string> m_filters;
+        std::string m_trimmed_name;
+    public:
+        SectionTracker( NameAndLocation const& nameAndLocation, TrackerContext& ctx, ITracker* parent );
+
+        bool isSectionTracker() const override;
+
+        bool isComplete() const override;
+
+        static SectionTracker& acquire( TrackerContext& ctx, NameAndLocation const& nameAndLocation );
+
+        void tryOpen();
+
+        void addInitialFilters( std::vector<std::string> const& filters );
+        void addNextFilters( std::vector<std::string> const& filters );
+    };
+
+} // namespace TestCaseTracking
+
+using TestCaseTracking::ITracker;
+using TestCaseTracking::TrackerContext;
+using TestCaseTracking::SectionTracker;
+
+} // namespace Catch
+
+#endif // TWOBLUECUBES_CATCH_TEST_CASE_TRACKER_HPP_INCLUDED