python-casacore and casatools

[r-xue]

Since Pipeline requires CASA6/casatools and the symbol-clashing prevents the interoperability of casatools and python-casacore: casacore/python-casacore#251 (workaround unclear), currently there is no direct solution to operate Pipeline + xradio (with ms-I/O capability) together under the same Python environments. Two possible solutions:

• xradio + casa-formats-io
• xradio + an additional casatools-based i/o "extension", a casatools/casatools translation layer, or monkeypatching those python-casacore refererences.