implement iOS 7 style.
change api for new style.
removed all old code. SIAlertView is now iOS 7 only.
tweak for proper shadow display
tweak layout code to support multiline title and message;
adjust size to mimic iOS 7’s native style.
drop old iOS version support
fine tune some comments
tweak default text attributes of title and message
exposed more attributes setters for theme support.
fine tuned button interactive state.
tweak helper function for generating highlighted background image
for buttons
fix setter no working
organize header’s code
change line drawing implementation for crisp line
update usage examples
refactor window related code to SISecondaryWindowRootViewController
update license
remove resources specifier in pod file
add convenience init api;
remove tint support
rewrite setter and getters to support changing theme on per instance bias.
add support for tint
fine tune highlight color calculation method
update example