Merge pull request #528 from darribas/master

Replacing 0 by min value in choropleths
fixes for 3.
refactoring
more fixes.
force 2 vs. 3 split
strip when python3
force 2 vs 3 formatting
no need to chuck back to bytes
geoda_quads option added
nosetests doesn't play well with homogeneity_test so renameing to homogenety
Adding option for geoda_quads in LISA related classes/methods for issue #390
removing 2_3 stuff that wasn't intended for this branch
Merge pull request #530 from sjsrey/i390

I390
Merge branch 'fast_wsubset' of github.com:darribas/pysal into fast_wsubset