Testsuite cleanups and improvements.

Add ctest support.
Add FileSystem::changeDirectory method.

src/nvcore/FileSystem.cpp

@@ -45,3 +45,11 @@ bool FileSystem::createDirectory(const char * path)
 #endif
 }
 
+bool FileSystem::changeDirectory(const char * path)
+{
+#if NV_OS_WIN32
+    return _chdir(path) != -1;
+#else
+    return chdir(path) != -1;
+#endif
+}

src/nvcore/FileSystem.h

@@ -13,6 +13,7 @@ namespace nv
 
 		NVCORE_API bool exists(const char * path);
 		NVCORE_API bool createDirectory(const char * path);
+		NVCORE_API bool changeDirectory(const char * path);
 
 	} // FileSystem namespace