*Title: Enhancements to the content browse

Incentive:
Add some enhancements to the browse page which one normally needs.
- Permission handling on nodes
- Cancelling a browse

*Documentation:
1.
Allow the browse to honour permission in the system by passing the permission
to check to the browse system.

New entries:
- permission - An associative array which contains the access method and the class to check,
               for instance one could give checkable options only to nodes which one can create a special class under.
               Contains:
               - access (required Name of content access to check, e.g. read, edit or create
               - contentclass_id (optional) Which class ID to include in checks, makes only sense for 'create' access.

2.
Make it possible to have a cancel button on the browse page.
One of the problem with adding a cancel button is that the browse form actually posts
back to the from_page, this means that page requesting the browse would have to handle
browsing itself.

Instead a new form is introduced which posts to content/browse and is placed next to
the Select button. The request will be pick up by browse.php and redirect to page.
Redirection follows these rules:
- cancel_page - If set from the browse request (client) it will redirect to that page
                Most clients that request browsing don't need this.
- from_page - If set from the browse request (client) it will redirect to that page
- No page was defined so it redirects to content/view/full/2

Note: Code placed in content/action or other non-visual pages should set the cancel_page,
if not the page will redirect back to a place where nothing happens.

*Testing:

*SVN Revisions: