Adding Menu functionality

For easy creation and manipulation of menus.
Menu-izing the admin top menu and tidying up some view sharing logics
Menu-izing the dashboard sidebar
Menu-izing the settings sidebar
Fixing InstallCommand
Pretty major refactoring of Settings

- Use a dumb Setting object to represent a setting
- Bit of interface segregation
- Overhauling how settings are formatted and outputted to a page
Adding a comment, that's worth a single commit, right?
Adding global before and after filters to hook into
Basic permissions system