v0.9.1

! performance optimization
! ifChanged callback
! unchecked radio buttons callbacks
+ case insensitive methods
+ indeterminate state support #closes38
+ 6 options:
determinateClass
determinateCheckboxClass
determinateRadioClass
indeterminateClass
indeterminateCheckboxClass
indeterminateRadioClass
+ 2 methods:
determinate
indeterminate
+ 3 callbacks:
ifDeterminate
ifIndeterminate
ifToggled