1.3.0

(#147):
Introduced 'async' feature which is moves work to a dedicated single-threaded feature scheduler, while being observable on the observation scheduler

(#148):
Updated mockito-kotlin library.

(#150):
Fixed Bootstrapper variance.

(#150):
Minor improvements to the new 'async' feature.

(#158):
Introduced an optional FeatureScheduler which can be used with non-async features.
This is useful when a feature is instantiated on a thread other than the thread it should be bound to (for example the UI thread).

When providing a FeatureScheduler, the feature is able to correctly switch to its desired thread rather than throwing an exception.

(#160):
Changed to Java 8 compatibility

(#161):
Improved the error message thrown by SameThreadVerifier. It now includes the feature's class name and the thread names.