First pass at rewriting WPAlertDialogFragment
Completed rewrite of WPAlertDialogFragment
Added handling of null arguments
Merge branch 'develop' of https://github.com/wordpress-mobile/WordPress-Android into issue/931-rewrite-alert-dialog

Conflicts:
	src/org/wordpress/android/util/WPAlertDialogFragment.java
Merge pull request #932 from wordpress-mobile/issue/931-rewrite-alert-dialog

Issue/931 rewrite WPAlertDialogFragment