New: added function find_cucappID in the helper category CPResponder+CuCapp

Previously, it was complicated to know if a cucappID was displayed or not.
Now, from the console you have access to the function find_cucappID which takes one param.
This function will print every current elements who responds to this cucappID.
This is very usefull for debugging.
Merge pull request #11 from Dogild/Helper

New: added function find_cucappID in the helper category CPResponder+CuCapp.j