Merge pull request #24 from Alcaro/master

Use the memory descriptor API.
Merge pull request #25 from Alcaro/master

Add a core option for GBA mode.
Merge pull request #26 from Alcaro/master

Add a core option for color correction.
Set performance level
Attempt to fix issue https://github.com/libretro/gambatte-libretro/issues/21
Merge pull request #28 from Alcaro/master

Fix overflows.
Merge pull request #29 from Alcaro/master

Get rid of 64KB lookup table that doesn't speed things up.
Build fix for OSX Mavericks
Fixed on game reload and a custom palette was used, it was lost on reset.
Added option to use a custom global palette from Core Options.
Merge pull request #30 from askotx/master

Fixed on game reload and a custom palette was used, it was lost on reset...
Merge pull request #31 from Alcaro/master

Fix possible buffer overflow.
Fix crash on too small ROMs. (I suspect it uses uninitialized stack memory gets different values for byte 0x147.)