docs(ngEventDirs): adding quick examples for new events

Closes #5338
docs($injector): use correct spacing convention for CoffeeScript functions

This convention is exhibited by http://coffeescript.org/ and https://github.com/polarmobile/coffeescript-style-guide#functions.

Closes #5354
docs(tutorial/step-4): fix typo

Closes #5356
docs(booleanAttrs): add @priority to all the boolean directives

Closes #5361
docs(ngCloak): style name is ng-cloak, not ngCloak

Closes #5374
docs($interval): remind the developer to destroy their intervals

It is essential that users of `$interval` destroy the interval when they are finished.
Otherwise you can get memory leaks.
Often `$intervals` are used in directives or controllers and developers don't think
about what happens when the component is destroyed.
If a directive/controller scope is destroyed, then the $interval should be destroyed as well.
This could cause some issues with developers who assume that the interval will be cleared
for them when the scope is destroyed.

Closes #5377

I believe that the library could/should handle this as well, but thats another issue.
Merge branch 'master' of https://github.com/angular/angular.js
componentizd!