move 3rd party js to vendor, cleanup old generated files

**Changes committed:**

*	deleted:    app/assets/javascripts/bootstrap-modal.js
*	deleted:    app/assets/javascripts/omniauth_callbacks.js.coffee
*	deleted:    app/assets/javascripts/proposals.js.coffee
*	deleted:    app/assets/javascripts/votes.js.coffee
*	renamed:    app/assets/javascripts/bootstrap-alert.js -> vendor/assets/javascripts/bootstrap-alert.js
*	renamed:    app/assets/javascripts/bootstrap-button.js -> vendor/assets/javascripts/bootstrap-button.js
*	renamed:    app/assets/javascripts/bootstrap-carousel.js -> vendor/assets/javascripts/bootstrap-carousel.js
*	renamed:    app/assets/javascripts/bootstrap-collapse.js -> vendor/assets/javascripts/bootstrap-collapse.js
*	renamed:    app/assets/javascripts/bootstrap-dropdown.js -> vendor/assets/javascripts/bootstrap-dropdown.js
*	renamed:    app/assets/javascripts/bootstrap-popover.js -> vendor/assets/javascripts/bootstrap-popover.js
*	renamed:    app/assets/javascripts/bootstrap-scrollspy.js -> vendor/assets/javascripts/bootstrap-scrollspy.js
*	renamed:    app/assets/javascripts/bootstrap-tab.js -> vendor/assets/javascripts/bootstrap-tab.js
*	renamed:    app/assets/javascripts/bootstrap-tooltip.js -> vendor/assets/javascripts/bootstrap-tooltip.js
*	renamed:    app/assets/javascripts/bootstrap-transition.js -> vendor/assets/javascripts/bootstrap-transition.js
*	renamed:    app/assets/javascripts/bootstrap-typeahead.js -> vendor/assets/javascripts/bootstrap-typeahead.js