Convert VNDS games to be usable with Higurashi-Vita.

What the conversion does:
	* Make all images 32 bit PNGs, bits used for ARGB.
		* This is to make sure libvita2d can load them. xerpi/libvita2d#57
	* Make the folder look like a Higurashi folder by moving the assets into different folders.
	* Extract ZIP files.
	* Create the "isvnds" file to identify the folder as a VNDS game for Higurashi-Vita
	* Detect .aac audio and convert it with FFmpeg, if possible.

How to use:
	* Get at least Higurashi-Vita v2.4+
	* Get VNDS game
	* If you have AAC audio in your game, install FFmpeg and make sure it's in PATH or in the same directory as the converter.
	* Extact the VNDS game ZIP file.
		* You don't need to extract sound.zip, background.zip, etc. yourself.
	* Launch the program
	* Select the root of the VNDS game folder.
        * Linux users will need to type in the path manually, Windows users can use a GUI.
	* Wait
	* The converted game will be at <original folder name>-converted
	* Put converted game folder in ux0:data/HIGURASHI/Games/