Adding DASPK 3.1 wrapper solver capabilities.

Basic capabilities now match that of DASSL.  Sensitivity analysis yet to be
tested.  Currently not relient on ADIFOR or MPI dependencies for automatic
differentiation.
Update readme for DASPK 3.1 to include source package URL.
Differentiate between lower and upper bandwidths of matrix in DASSL.

ML = self.bandwidths[0]
MU = self.bandwidths[1]

Also fixed small typo.  Since we currently do not specify bandwidths in RMG-Py,
we have not found this error.
Initialize iwork and rwork properly according to DASPK documentation.
Added daspk test case for sensitivity analysis using simple batch reactor model.
Create external cython declaration files.
Make daspk an optional make target.  When 'make' is typed, only make pydas.

This way, users don't have to use or download daspk3.1 unless they want to.
Separate the unit tests into DASPK and DASSL tests.

Keep them separate so users do not need to install DASPK3.1 but can still
run the DASSL unit test.
Remove print statement in cython setup.py file.
Fix res function in DASPK model to return only a NY-lengthed array.

For finite difference sensitivities.  Otherwise, results in memory leak
and segmentation fault in DASPK.
Provide printing and plotting of sensitivities in DASPK Test.
Added printing of sensitivity results.  Finally working!
Provide user supplied RES when running sensitivity analysis using DASPK.
Update Mac installation instructions in README.rst

I think these instructions work with the latest homebrew and MacOS X 10.9.3
Updated Josh's email address.

To one that actually still works.