1.9.0

88bfe0d Add outer circle alpha target option (#154)
1bdfa87 Add jittered shadow fallback for transparent targets (#151)
befa6aa Dont attempt to create layouts with negative width (#147)
ba0c355 Signal when last target was not clicked if continueOnCancel is true (#142)
5576f82 Return TapTargets in all factory methods (#135)
c10d2f2 Extend AnimatorListenerAdapter (#131)
17e1f05 Reduce some visibility to package protected (#132)
53f66c8 Use ContextCompat.getColor() (#130)