PLT-2992 Added the ability to use different themes for each team (#3411)

* 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

webapp/components/setting_item_max.jsx

@@ -84,6 +84,7 @@ export default class SettingItemMax extends React.Component {
                         </li>
                         <li className='setting-list-item'>
                             <hr/>
+                            {this.props.submitExtra}
                             {serverError}
                             {clientError}
                             {submit}
@@ -113,5 +114,6 @@ SettingItemMax.propTypes = {
     updateSection: React.PropTypes.func,
     submit: React.PropTypes.func,
     title: React.PropTypes.node,
-    width: React.PropTypes.string
+    width: React.PropTypes.string,
+    submitExtra: React.PropTypes.node
 };