PEP 8 cleaning
More clean up
blaze.datashape -> datashape and blaze.pi -> math.pi
Merge pull request #159 from aterrel/import_cleanup

Import cleanup
Document SQL blaze backend
Write about missing features
Update cffi test for dshape move
Add cffi to travis-ci test
Enable previously skipped slice tests
Enable append error test, use data descriptor capabilities
Remove outdated py_interp test (can no longer pass in strategy to blaze.eval())
Merge pull request #162 from markflorisson88/blazetests

Blazetests
Merge pull request #161 from markflorisson88/sqldocs

Sqldocs