Lopez Lab, minimum changes needed for how we use pysb

I've kept the minimal patch set that we use for modeling. This patch set fixes

(1) Allows for comparisions (eq, ne) of core PySB objects with the exception of Rule Patterns
(2) changed <interactive> to _interactive_ such that one can run BNG tools from the command line
(3) Several additional macros (and allowing None in macro calls)
(4) Test cases for all new additions
(5) Added compartments to comparisons