Adaptable cube size and snake button

- The GUI can now display and simulate every size of cube, just change
the "dim" variable in the "globalVars" file (connect to a cube which
isn't a 8^3 cube will require some modifications in the SerialComm
class)
- You can now enable the snake game with a button and return in the
frame edit mode if you want.
- "Select file" button now works, it was a conflict between my "File"
class and the java one

- Always some errors when playing with frames