Merge pull request #72 in CASA/casa6 from CAS-12713 to master
* commit 'd5ecb00ca913e6227638223f7afb2ca9066d416f': CAS-12713 improve readability of restfreqtool.py
minor formatting change CAS-12713 add test for cubesource mode
removed unnecessary line
fix an error when specmode is cubesource
add specmode parameter to tsdimaging