adding tests for features to come
Refactored monos, added many features to posys

 - Created a template 'nomials' class for shared features
 - added 'eid' attribute to monomials (it's basically a hash of 'exp')
 - added algebraic simplification to both monomials and posynomials
 - added posynomial-posynomial multiplication
removed old files
removed matrix bits
Fixed small error, thanks to tests
more vector and constraint tests
fixed posynomial division
swapping out lambdas
Merge branch 'tests' into matrices
switched to arrays
switched to using arrays!
Merge branch 'nomials' into matrices

Conflicts:
	gpkit/__init__.py
	gpkit/utils.py