Added two extra UIAlertView APIs. Refactored the initWithTitle a bit for...

... this. Demo code in the “Custom” button of the demo project

When these two new methods are available, it is easier to write a block-based wrapping for LMAlertView. LMAlertView. LMAlertView can then be a drop-in replacement for UIAlertView in for instance code like https://github.com/jivadevoe/UIAlertView-Blocks