Adjusted BasicTransformationProperty to return MutableProperty instances instead of PropertySource.
Switched naming convention for MutableProperty and PropertySource getters from getXXX() to xXX(). The previous convention felt too unnatural (especially for MutableProperty because one needed getXXX to set the value).
Introduced TransformedImageDisplay.addLazyTransformationUpdater.
Removed "experimental" flag from SimpleAsyncImageDisplay (it will be soon deprecated).
Added BasicTransformedImageDisplay (untested).