Added declaration for camera_control_initialize();

Should fix this error at compilation phase: ```implicit declaration of
function 'camera_control_initialize' is invalid in C99```
Better button_array example for Processing

We now print all buttons and the comments are more detailled.
rge remote-tracking branch 'upstream/master'
Merge pull request #74 from SableRaf/master

Cleaner camera initialize + Better Processing button example