[Owncloud] Merge request: Editing multiple calendars

[Bart Visscher]

Hi Thomas,

Some remarks:
- Use OC_JSON::checkLoggedIn() in new code instead of OC_USER::isLoggedIn & die
for example in apps/contacts/ajax/contacts.php
- Comment in apps/contacts/ajax/activation.php: yes there is a OC_JSON::error() function
- Use OC_Contacts_App::getAddressbook($id) instead of OC_Contacts_Addressbook::find($id), it contains access checks. for example in apps/contacts/ajax/activation.php, and move it here before the setActive. 
- also for OC_Contacts_VCard::find($contact)
- space is not used in apps/contacts/js/interface.js
- don't add addressbook to function names in OC_Contacts_Addressbook, this is redundant and a 'bug' in the calendar app
- in apps/contacts/templates/index.php first parameter of OC_Helper::linkTo is a app name, so 'contacts'

Other than this, looking good.

Bart