Fix click+scroll events for nucleus. Prevent memory leaks.

Events done yesterday are giving problems. Things are leaking off b/w
meteor's reactivity and event sync. Biggest problem till now was memory
leaks which were filling up my 8Gigs pretty fast and chrome got
hanged. That is solved now. Also after testing many times when trying to
do other events, I realized the events were not reliable, i.e they got
skipped sometime. This commit solves this problem for nucleus window but
it still exists for app.

I should have done many small commits till now and two big ones for
those two fixes.

LESSON_LEARNED: Commit frequently bitch, commit frequently.
Fixed bug in click events for app.

They were leaking into the nucleus window because of little silly thing
I did. There is still little problem with initializing event handlers in
the app. This stupid shit is eating today's day as well. I was supposed
to be doing mup task today.
Make event initialization more reliable.

Nailed it this time. Or so I suppose.
Added check to not sync clicks on any of the "Sync" buttons in toolbar.

FIX: In future, we might need to replace this check with something like "check if this click happened in Toolbox" or something