Aztec solver implemented

-The Aztec solver routine works. The other solver routines have been commented out for now.
-The MPI structure is in the code but running with more than one processor gives an output related error
-More variables are allocated now than probably need to be, this is a place for improvement.
-The solver options used in this commit converge within 200 iterations to 1.0e-10
Merge branch 'master' of https://github.com/alexlongne/parpetro