HTML safing error messages.
Removed unused, really old school JS file with common helper methods (addEvent :-).
Removed leftover reference to initRow highlighting.
Converted the tab switching code to a jQuery plugin with the least changes possible. Now it doesn't depend on prototype.js any more.
Removed scaffold styles.
Removed prototype.js, and using $ everywhere for jQuery access now.
Removed stub implementation of selecting tax in place for now.
Namespaced all JS initializer functions, which also simplifies the loading code.
Renamed tab_ctrl and moved it to (jquery_)plugins directory
Re-added deleting invoices.
Moved tax calculation in the expense/invoice forms to jQuery plugin.
Fixed navigation highlighting everywhere with the active_link_to gem.
Updated README.