perf($parse) use a faster path when the number of path parts is low

Use a faster path when the number of path tokens is low (ie the common case).
This results in a better than 19x improvement in the time spent in $parse and
produces output that is about the same speed in chrome and substantially faster
in firefox.
http://jsperf.com/angularjs-parse-getter/6

Closes #5359
fix(closure): add type definition for Scope#$watchCollection

Closes #5475
Merge branch 'master' of https://github.com/angular/angular.js
componentizd!