changing the 'change view layout' link on view/blocks.php to 'change my view layout', and removing the confusing image

fixing bug where users are unable to give logged in users, friends, public or groups access to views
problem caused by me changing what I thought were just language strings, which messed everything up

Correct the path to the view layout preview thumbnails, so it works when Mahara is installed in a subdirectory.

Conflicts:

	htdocs/lib/form/elements/userlist.php

adding confirm dialog to cancel with new view, and cancelling now deletes the partially created view

Now it clarifies that what you are viewing is only a rough representation of the original. There's a back link to go back to the files section or whatever previous page you were on. The message has been styled a bit too.

added message about tagging as 'profile' to make artefacts go in the sideblock

added check so main menu is only displayed when not empty

unread messages in sideblock works now :D

added logout link

appears on every page with a sidebar when logged in
contains unread messages, pending friends, groups invited to, groups owned, views tagged with 'profile'

add better messages for when there are no groups to display