chore(grunt): update to latest jshint task

Upgrade JSHint task from ~0.6.4 to ~0.7.2. Two useful changes: ability
to set jshintrc option to use jshint's native ability for finding .jshintrc
files relative to the linted files and update jshint to 2.3.0.

Closes #5143
chore(travis): use only websockets and xhr-polling

I wanna see more info about BrowserStack...
chore(travis): tolerate 2 disconnects to make the build more stable
chore(deps): use regular junit-reporter

We don't need the special branch anymore.
chore: use karma-browserstack-launcher from master
chore(travis): fix the build id on browser stack

This just improves the way BrowserStack groups the sessions.
Merge branch 'master' of https://github.com/angular/angular.js
componentizd!