improve alertViewStyle enum
add textFields to alert
test alerts with textFields
since we want to manipulate the UITextFields from outside the class we have to alloc them early, we can't wait until show is called!
move alert up when keyboard appears
remove keyboard frame observer before resigning first responder, so the alert view scales without moving to the bottom
after "animate in" animation is done make textField first responder
configure secure text entry options
make MBAlert 3 button example to use destructive button
add cancel button to alerts with text field
make AnimationKeys static
add enable blocks to buttons that are evaluated when the text of the textFields change
use UIButton as a parameter to the "enable" block. So we can manipulate the button, i.e. the title of the button
set adjustsFontSizeToFitWidth to YES to actually resize the font in the UIButton
implement enable method that changes the text of the button depending on the length of the text in the field