First draft of admin tabs, still to make several functions more dynamic.
Made generic the render fields and render settings functions for reuse.
Makes validate_settings function more generic, and simplifies the settings sections function.
Adds instructions in the comments
Merge branch 'master' of github.com:jeffikus/starter-plugin into feature-admin-tabs
Implements a singleton pattern in the Starter_Plugin_Admin class.
Implements a singleton pattern in the Starter_Plugin_Settings class.
Corrects get_instance() to instance() in the main plugin class.
Adjusts the docblock on the instance() method in the Starter_Plugin_Admin class.
Adjusts the plugin header comment to differentiate the plugin URI and author URI.
Merge branch 'master' into feature-admin-tabs
Separates the tab key getting logic into a private method. Adds escaping functions at output of the settings tabs.
Abstracts the admin screen header tag logic into private methods. Creates a 'magic switch' to activate the tabbed interface if there is more than one settings sections registered. If not, use a standard layout with no navigation tabs.
Adjusts the validation method to use the new _get_current_tab() private method.
Removes unnecessary code comments from the Starter_Plugin_Admin class.
Adjusts the starter-plugin-get-admin-header-data filter key.
Adjusts the example settings to separate standard field types and special, WordPress-centric, field types.
Adds a get_settings() method to the Starter_Plugin_Settings class.