Update a2600.hsi

Took out the PAL carts as the screen is not centered properly on NTSC. See new file a2600p.hsi for the PAL roms.
Create a2600p.hsi

These are the Atari 2600 roms that run on PAL (a2600p in MESS), split off from the original a2600.hsi
Merge branch 'master' of git://github.com/Gitweazle/MAMEHub into Gitweazle-master