Fixed UIAlertView on Login screen

Changed the behavior of the UIAlertView in the ABCLoginViewController to be a better user experience. Also changed a few comments to make them more accurate.
Fixed typos/standardized text in settings

Fixed a typo and standardized the use of "Backend" as opposed to use of "Backend URL" on the settings screen.
Changed some text on settings screen and alert

Changed some text on settings screen to be more standardized also changed the UIAlertView to get rid of the title.
Merge pull request #1 from cbrough/fix-login-alert

Fix login alert