cleanup pininput a bit and reuse shutdown functionality of VP when pressing escape key long enough for keyboard, too

..reuses "Exitconfirm" registry setting (new default is 2 secs)

git-svn-id: svn://svn.code.sf.net/p/vpinball/code/trunk@931 14438d79-0ffd-4333-8ae7-ea2bdd901387