rx(1) tests for "testDeliverLatestToView_ViewComesAndGoes"

[StefMa]

In #137 @GrahamBorland created a really cool test called testDeliverLatestToView_SingleItemViewComesAndGoes & testDeliverLatestToView_ViewComesAndGoes

Since these tests are very great but not part of the "original" rx (rx1) module we wanted to have these two tests in the rx module as well.

This issue is about to adding these tests to the rx-module and adjust (if needed) the behaviour...