Updating to latest version of the cookoff

The build system is made to use the python functionalities of the cookoff
developed for BEM++. As a result, we are switching from nose to pytest. In
practice, the differences are fairly small between the two testing
frameworks.

The python dependencies are now included in a separate file.
Incorrect permission on a file
Version bump by patch number

Also PEP-8ed the setup.py file.
And made casa install not fail if buildtask does not work.
Installation with CASA 4.2.2 on mac

Partially addresses #45. The purify installer calls install_name_tool so
libpython2.7.dylib is referred to with an absolute path. It is not clear why it
isn't absolute in the first place since it appears with an absolute path on the
commandline during linking. Might be because it is part of a python framework
belonguing to the CASA app. Mysterious are the ways of the Mac.
Adds test function to run all tests
Triple-second-guesses CASA 4.2.2 peculiarities
Remove cython/cmake stuff that is now in cookoff
Lookup older version of CFitsIO when running in CASA

CASA uses software way past its peremption date. It provides tar file
for some of this software.
When running a casa install, the missing headers for the casa version of
CFitsIO are obtained from the NRAO website and added to the CASA
install.
Update install instructions for CASA+Linux
Generated subdirectory given explicit build dir
On Mac, up to date CFitsIO is used

It is not clear which CFitsIO comes with CASA on mac. But compiling with
the newest one seems to work.
Merge pull request #47 from UCL/features/update_cookoff

Features/update cookoff