Updated dist_mac sed usage so it works with the version of sed on the mac.
Added Known Issues section to README.
Added smarts for working on Mac. Removed hardcoded path.

Added smarts to prevent script from trying to start casapy on a Mac (this
currently cannot be done); instead it prints the casapy command that the user
should enter manually.
Gave user responsibility for execution path, Python path, and analysisUtils.

Added function to check that casa_call module exists in the Python path.

Added README instructions to include distribution directory in the shell
execution path and the in the casapy Python path.

Removed addition of analysisUtils directory from Python module search path.
(It was only available to computers on the NRAO CV network; was not available
from NRAO CV Mac, kwaltz). Since computers not on the CV network will need a
special installation, and since not all CASA guides require analysisUtils, I
will leave it to the user to install and setup analysisUtils when it is needed.
Instructions, referring the user to the analysisUtils wiki page have been
included in the README.
Merge branch 'cleanup'

Conflicts:
	README

Merging Mac developments with Linux developments.