Move out node assignment handling from content/edit

*Title: Move out node assignment handling from content/edit

Incentive:
By not having the node assignment list in content/edit you will gain more space for other
more important elements. This will also allow nodes placements to be handled outside of content/edit.

*Documentation:
A new INI switch is added which will enabled/disable the controls in content/edit. It can be
enabled for backwards compatability.

The node handling is now moved out to the navigation interface.

New global template variables:

New global HTTP variables:
UseNodeAssigments - This is set when the controls are disabled and set to the value '0'
                    If '0' the edit code will skip all node handling.

New INI variables:
content.ini:
[EditSettings]
EmbedNodeAssignmentHandling - Controls the inclusion of node assignment handling controls in content/edit
                              'enabled' to enable, 'disabled' to disable.
                              If disabled these template variables will no longer be available:
                              assigned_node_array, assigned_remote_map, published_node_array and main_node_id.


*Testing:

*SVN Revisions: