Feature - remember gbc_bios.bin location

[milesrotaru]

This is a necessity for large ROM collections spanning multiple folders. As a workaround I have to load a copy of Tetris which I've placed in the top directory along with the GBC bios file before I intend to load any other game which uses it. The easiest solution would be to just always look for gbc_bios.bin in the same folder as gameyob.nds first.

[Stewmath]

There's an option in gameyob.ini to specify the bios path, currently it needs to be filled in manually. I guess once the bios is detected I can make it fill in that option automatically.