Merge pull request #37 from libretro/master

Libretro updates
[Core/General] added optional dynamic allocation of cartridge/CD hardware buffer
[Core/MS/GG] fixed SP register initialization on power-on (Ace of Aces, Shadow Dancer, Ecco the Dolphin, Evander Holyfield Real Deal Boxing)
[Core/MS] improved emulation of Japanese Master System I/O chip (315-5297)
[Core/MS] improved SG-1000 & Mark-III hardware emulation
[Core/MS] improved console hardware auto-detection
[Core/MS] fixed BIOS ROM loading when switching system hardware
[Core/GG] added LCD ghosting software filter
[Gamecube/Wii] Japanese Master System model has no reset button
[Gamecube/Wii] changed VI encoder code license to libogc
Merge branch 'master' of github.com:ekeeke/Genesis-Plus-GX
[Core/General] added optional dynamic allocation of cartridge/CD hardware buffer (continued)
Merge pull request #12 from Oggom/master

Sync with main repo