change mupen64plus video plugin from Glide64 to Glide64mk2

Glide64mk2 is the only plugin that correctly supports all testing ROMS, especially those from N64.tar.gz in the box-box. I haven't tried z64, though.

These are all the DLLs that currently get installed for mupen64plus: http://slexy.org/view/s20fNBO051