* [sqllab] add support for results backends
Long running SQL queries (beyond the scope of a web request) can now use
a k/v store to hold their result sets.
* Addressing comments, fixed js tests
* Fixing mysql has gone away
* Adressing more comments
* Touchups
* pull explore actions button group into component
* use button component
* make sure we render all action buttons
* test that embed code is correct
* don't need before each
* generalize modal trigger for use with plain links or icons