Move math and some file and data conversion files out from native to Common.

Buildfixing

Move some file util files

Buildfix

Move KeyMap.cpp/h to Core where they belong better.

libretro buildfix attempt

Move ini_file

More buildfixes

Core/FileLoaders/DiskCachingFileLoader.cpp

@@ -23,8 +23,8 @@
 
 #include "ppsspp_config.h"
 #include "file/file_util.h"
-#include "file/free.h"
 #include "Common/Data/Encoding/Utf8.h"
+#include "Common/File/DiskFree.h"
 #include "Common/FileUtil.h"
 #include "Common/CommonWindows.h"
 #include "Core/FileLoaders/DiskCachingFileLoader.h"