* PLT-3695 unitying upgrade support
* PLT-3695 refactoring to use sql_upgrader
* Fixing unit test
* Adding 3.3 to 3.4
* Fixing upgrading
* Seperating DB schema from version.go
* Fixing upgrade cmd
* Moving to const for exit codes
* remving old unused code
* Cleaned up user_settings_theme.jsx and import_theme_modal.jsx
* Made ImportThemeModal use a callback to return the theme to the user settings modal instead of saving it directly
* Moved user theme from model to preferences
* Added serverside API to delete preferences TODO update package with client stuff
* Changed constants.jsx so that Preferences and ActionTypes can be imported on their own
* Updated ThemeProps migration code to properly rename solarized code themes
* Fixed warnings thrown by AppDispatcher
* Added clientside UI to support team-specific themes
* Removed debugging code from test
* Fixed setting a user's theme when they haven't set their theme before
