Added controls for the picade to gngeorc file

Hi,

Not sure if you've seen the Picade
    http://www.kickstarter.com/projects/pimoroni/picade-the-arcade-cabinet-kit-for-your-raspberry-p

Seems like PiMAME will be quite popular with it so it could be a good idea to include some good configuration in the cfg files. Not sure if you have any future plans for this in PiMAME but here is the neogeo cfg.

I've also got a good setup for pisnes but from their source code it seems they hardcode the configuration file needed (rather than using a dotfile)
    https://code.google.com/p/pisnes/source/browse/unix/unix.cpp#229

From the looks of the install script you include a .zip of pisnes from your own server? Perhaps that zip could have the pisnes cfg updated with the following configuration?
```
[Keyboard]
# Picade Controls
A_1=122
B_1=304
X_1=308
Y_1=306
L_1=32
R_1=120
START_1=49
SELECT_1=53
LEFT_1=276
RIGHT_1=275
UP_1=273
DOWN_1=274
QUIT=27
ACCEL=8
```