Pull request #647: CAS-13942
Merge in CASA/casa6 from CAS-13942 to master
* commit '0f0d268ecb647e18fcc4e994cbe0813fa1ab3fa5':
make the behavior for 2 sided shapes as before when using flux instead of sample. This fix some failures in test_simobserve
Implemented reviewer's suggestions + some cleanup
Fixed a problem arising from SkyComponent::flux returning a fixed number when spectralModel is of the varying kind. Now used the SkyComponent::sample method