[WIP] redesign calendar app

Work in progress on introducing a sidebar in the calendar app to provide simpler navigation through the users calendars. Also the datepicker has been restyled to improve accessibility and clean up the UI.

Refer to https://github.com/owncloud/calendar/issues/269 for earlier discussion about the new design. Let's continue here to iron out the details.

Reference screenshot:
![untitled](https://f.cloud.github.com/assets/639688/2308838/b9e9140a-a2c5-11e3-9846-ce52853b5edb.png)

Checklist:
- [x] https://github.com/owncloud/calendar/issues/332 https://github.com/owncloud/calendar/issues/77 the calendar color should be in the calendar list on the left. Ideally just make it be the background of the checkbox (see Google Calendar, where the color box is the checkbox)
- [x] the calendar grid doesn’t seem to extend all the way to the bottom? There’s like 10–15 pixels whitespace left to the bottom of the screenshot
- [x] https://github.com/owncloud/calendar/issues/274 speed up settings menu
- [x] The settings area should not use tables (https://github.com/owncloud/calendar/pull/359#issuecomment-36745338 https://github.com/owncloud/calendar/pull/359#issuecomment-36747695)
- [x] Settings content should not exceed settings menu (https://github.com/owncloud/calendar/pull/359#issuecomment-36745338)
- [x] Rename a "hidden" calendar shows the calendar appointments after saving it (https://github.com/owncloud/calendar/pull/359#issuecomment-36745338)
- [x] Fix Firefox/Linux rendering (https://github.com/owncloud/calendar/pull/359#issuecomment-36746197 https://github.com/owncloud/calendar/pull/359#issuecomment-36747161)
- [x] Fix transparent checkbox color for some calendars (https://github.com/owncloud/calendar/pull/359#issuecomment-37561609)
- [x] Fix share icon for shared calendars (https://github.com/owncloud/calendar/pull/359#issuecomment-37561609)