Fixes #48, [testRunner] tokenView and traceView can be out of sync if test runs fast
Added currentLocation() to FileViewModel which should only
be defined when both (all) subviews show info for the same location.
Made TokenViewModel current expression depend upon FileViewModel.currentLocaiton
selectTokenInSource now reports which token was selected.
All tests updated to expect selected token.
PatientSelector refactored to shorten selectTokenInSource.
Avoid test flakiness by checking
that the lastChange load completes before the next test step