Unsetting CFitsIO variables during lookup

This avoids cmake complaining about undefined variables.
Moved some cmake stuff to the cook-off

See issue #5.
Moves PythonPackage and PythonVirtualEnv.
These two packages are used in BEM++ as well (bempp/bempp#71).
Find a coherent python install from cookoff recipe

Goes towards issue #5. The CoherentPython package makes sure (tries to) that the python executable
and the python libraries are the same. This is also used in bempp/bempp#71.
Updating to latest GreatCMakeCookOff
Add 'python' label to python tests
add patterns to gitignore
Add original file to cython dependency list
Passing BLAS when building Sopt locally
Add config file to projects

makes it easier to include version or ther information.
also declares the name of the blas file to include.
Merge branch 'features/with_sopt' of github.com:UCL/purify into features/with_sopt
Run nosetest even for python <= 2.6

Older pythons do not take to the "-m nose" command-line argument to well.
Replaced it with ``-c "import nose; nose.run()"``
Add nosetest changes from commit b7c19e3760fbee59fbdec8e77057e29e5ad76c3a
Re-enables some test

Disabled for debug purposes at some point. Should not have been committed
(1d21eff23c6b8561f008e50d3ae93fc793079725).
PyArray_DATA rather than generic buffer interface

for the sake of older numpys without the newer python buffer interface.
The main issue is accessing pointers to the underlying data for
both complex and real arrays.
This is what the buffer interface allows us to do.
On the other hand, the normal cython numpy interface expects an explicit
type. It is simpler to roll out are own typeless for those arrays that
could be either complex or real.
In a few years / CASA upgrades, it may be forthwhile to replace all calls to
this interface with the normal cython buffer interface. One should look at the
changeset when this particular file was introduced.

In the same vain, numpy arrays are created explicitly with order="C".
Passing test on legion+intel+mkl
Use environment script for purify_test

This should make it possible to run test when sopt is compiled as an external project.
Uses the Environment script facility of UCL/GreatCMakeCookOff/bd38520a4ccd430bceb189f4312568dd165b1bbe.
Merge branch 'features/with_sopt' of github.com:UCL/purify into features/with_sopt
Adds python libraries to python modules
untyped_pointer_to_data does not ignore the exception it raises
visibilities passed as numpy array to numpy interface