new file format with versioning and layer opacity

src/version.cpp

@@ -4,6 +4,10 @@
 const char* g_version = PP_VERSION_STRING;
 const char* g_version_number = PP_VERSION_NUMBER_STRING;
 const char* g_window_title = "PanoPainter " PP_VERSION_NUMBER_STRING;
+const int g_version_major = PP_VERSION_MAJOR;
+const int g_version_minor = PP_VERSION_MINOR;
+const int g_version_fix = PP_VERSION_FIX;
+const int g_version_build = PP_VERSION_BUILD;
 
 #ifdef _WIN32
 #include "windows.h"