remove old landing page
remove prefpane headings
show the main panel when the page is loaded
fix history management and refactor navigation for prefpanes
make app handler rules for richlistitems more specific to #handlersView
implement new category list using richlistitems
add styles for new category list
remove legacy styles and specify a max-width for the prefpanes
pre-process in-content styles
remove executable flag from applications.js
add some more captions for pref groups
fix selectCategory()