3dssms: Sega Master System emulator

Hi,

Here is an alpha port of smsplus to the 3ds :

- Install 3dsx or cia
- Put roms in "/3ds/sms/roms"
- Play !

Here is the status :
- No sound
- 16 pixels cropped on each sides ...

Changelog v02:
- fix exit emulator with .3dsx
- enable zipped rom's

Source code and improvements are to come in a week or two..