Added a very preliminary version of the SQL cache proposal for Blaze.
Added some use cases for the design document for SQL cache
Relabeled sections as per Mark suggestions
Added an implementation outline section as Mark suggested.
Using deferred arrays syntax now
Merge branch 'master' of https://github.com/ContinuumIO/blaze into sql-cache
Added a complete example
New modifications based on discussions
Merge pull request #166 from FrancescAlted/sql-cache

A proposal for a simple SQL cache for Blaze.
Removing pykit dependency
Remove pykit install in travis and jenkins
Merge pull request #187 from aterrel/remove_pykit

Removing pykit dependency.
Python 3 fix
Adding dynd install from source for travis.