Linux compilation.

[napnaps]

First of all, thanks you for this plugin, I thinked about it this morning and it exist !

On linux, It works, but you have to add in ofxSharedMemory.h :

#include <sys/mman.h>
#include <fcntl.h> 

Tested on ubuntu 12.04 kernel 3.2.

I've made a bunch test to share output between OF applications, I added an unsigned char array in the CustomData class (fixed with the good size), filled with data of ofImage::grabScreen and it works ! Futhermore I haven't made performance test yet...