Added new CacheDisk class, which caches frames to the hard drive, dramatically speeding up preview speeds, at the expense of IO operations. New unittests for caching framework. Fixed a few bugs with Frame constructor, which was causing invalid # width & height. Integrated JSON into the cache framework, to quickly share the state of the cache (including ranges of cached frame numbers). Fixed a bug where some Timeline frames could have no audio samples.

tests/ReaderBase_Tests.cpp

@@ -40,7 +40,7 @@ TEST(ReaderBase_Derived_Class)
 	{
 	public:
 		TestReader() { };
-		CacheMemory* GetCache() { return NULL; };
+		CacheBase* GetCache() { return NULL; };
 		tr1::shared_ptr<Frame> GetFrame(long int number) { tr1::shared_ptr<Frame> f(new Frame()); return f; }
 		void Close() { };
 		void Open() { };