Merge pull request #396 in CASA/casa6 from CAS-13442 to master
* commit 'c0daec9fd7479974b612a62556dc0c38c1cb217a':
Use initializer list constructor of IPosition
Update casacore poointer to latest changes in master Fixes partially CAS-13442
update casacore and adjust to removal of Mutex.h (CAS-13442)