Added template tag slugurl

Added a new tag that returns a page URL according to the page slug.
Include datepicker translations (fixes #167)

This includes all available translations for datepicker (version 1.10.3).
It also contains a list of all available translations in order to check
that the translation exists before including the translation file.
Finally, it puts the <script> for the translation inside the {% compress
%} tag.
Fall back on username in moderation panel if full name not defined
Remove {% get_localized_datepicker_js %} from ...

{% compress %} tag to enable offline compression
Add comment to remember why the tag is outside ...

compress.
Merge branch 'master' of https://github.com/jmiguelv/wagtail into jmiguelv-master
Add missing Page import
add tests for pageurl / slugurl
return None rather than '#' when no match found by slugurl
changelog / contributors update for #166
only show wagtailuserbar if page.id is defined - prevents error when previewing during page creation
gs
Removed trailing spaces from wagtailadmin scss files
Merge branch 'master' of github.com:balazs-endresz/wagtail
Removed trailing spaces from wagtailadmin js files
Remove redundant parameters from wagtailuserbar tag; trigger a DeprecationWarning if people are still passing a css path
Refactor wagtailuserbar logic - no need to split it between templatetags and views
Merge branch 'master' of github.com:torchbox/wagtail
Remove jquery-ui-i18n.js
Added collapsible multi-field panels