jQuery rewrite of config options show/hide/all.

This will replace showConfig + showConfigAll globally once @onli has
switched the parts which don't use the smartified code base yet. It
also adds a sensible no-js fallback and proper state indicators.
Merge branch '2.0' of github.com:s9y/Serendipity into 2.0

Conflicts:
	templates/2k11/admin/serendipity_editor.js.tpl