Added ability for adding a background image to the message and title views.  Updated to create a layer the title can sit inside of.  Added ability to change title/message/container background color.  Added ability to change the duration for default transition, along with dropdown transition since these are the only ones i'm using at the moment.  finally, added a mutable dictionary to hold buttonColors, so that button colors can be customized.  Probably should move button creation into a sepearate class to manage this instead.