* [utils] gathering/refactoring into a "utils/" folder
Moving current utils.py into utils/core.py and moving other *util*
modules under this new "utils/" as well.
Following steps include eroding at "utils/core.py" and breaking it down
into smaller modules.
* Improve tests
* Make loading examples in scope for tests
* Remove test class attrs examples_loaded and requires_examples
* move access permissions methods to security manager
* consolidate all security methods into SupersetSecurityManager
* update security method calls
* update calls from tests
* move get_or_create_main_db to utils
* raise if supersetsecuritymanager is not extended
* rename sm to security_manager
* [sqllab] improve Hive support
* Fix "Transport not open" bug
* Getting progress bar to show
* Bump pyhive to 0.4.0
* Getting [Track Job] button to show
* Fix testzz