make-compton: Added grafical way of enabling and disabling compton.

I've made a script that allows the activation and deactivation of Compton's effects through systems settings.

Some modifications have been made like the fact that some scripts have been moved to separate files to avoid writing "" before some special characters and to "clean" the helper up.

Zenity is being used to ask the user what to do so "zenity" have been added in the "dependencies" section of the package.

I hope everything is correct now.

helpers/DATA/compton/trisquel-compton-switcher

 #!/bin/bash
 
 #Check if compton is currently running.
-case "$(pidof compton | wc -w)" in
+case "$(pgrep -u $USER compton | wc -w)" in
     
     0)  COMPTON_RUNNING=false
 	;;