rename the GPC modular

@karlnapf 
this is a big patch.
I just test it at one shot.
I will send a PR for the notebook tomorrow since switching different branch is annoying when some error occurs in this PR 
@votjakovr thanks a ton for your comments - that is *really* appreciated ( as I am swamped with email from shogun /gsoc/workshop).
@yorkerlin please discuss things with roman - lots of potential nice synergistic effects here