Set HVAC temp asynchronously

The submitted patch of ag/162598687 (patch 6) did not include the final
changes made the to HVAC controller and the XML fixes (patch 5). Adding
those changes that should have been included, namely async setting the
hvac temperature and making the adjustable temperature button values
overlayable.

Bug: 162598687
Test: atest AdjustableTemperatureViewTest
Test: atest HvacControllerTest
Test: atest TemperatureTextViewTest
Change-Id: Ieaaf4b1e8ea892ac2c16f4aec028c357277e8ae7