Add definitions for angular-protractor 1.0.0-rc4
Changes based on @BillArmstrong's feedback
* Remove optional parameters from Element interface
* Remove additional parameters from ElementFinder.isElementPresent
* Add "asElementFinders_" and "then" methods to ElementArrayFinder interface
Merge pull request #2513 from isibner/master

Add definitions for angular-protractor 1.0.0-rc4