Merge branch 'new-django', remote-tracking branch 'origin' into new-django
Thanks to jshint, fixed a number of minor errors in WindowMaker.js
Fix error in server-side of "Show all skeletons"
New file maintenance.py for server-side administrative work.

First two functions:
 * find_empty_neurons()
 * neuron_treenode_counts(neuron_ids)
In 3D Window, "Save" is now "Screenshot".
WbGLApp.updateActiveNode now calls self.render()
Fix tag filtering in treenode table
Switched to standard transaction middleware and custom AJAX exception handling middleware.
Fixing lack of name for a requestQueue.replace
Better documentation for tracingtool to appear in the "?" widget.
New buttons to the review widget: reset all reviews, reset reviews by others
and reset own reviews. Regulated by user ownership access and accessible
for superusers where appropriate.
Fix to unused function can_edit_all_or_fail
Fixes to the functionality to alter the revision state of skeleton nodes.
Namely ask for confirmation and also fix errors in the server side,
and better reporting of treenode ownership.
Cleaner code for determining the type of node in the treenode table.
Display the reviewer's user name in the treenode table.
Removed confusing function "createConnector"
and replaced it by appropriate calls to createLink or
createSingleConnector with a continuation to createLink.

Also renamed createNodeWithConnector to createPostsynapticTreenode.
Added missing $ to urls.py
Corrected names of treenode table and also made some of them shorter.
Do not query for parent treenodes if the whole skeleton is loaded.
Speed up for treenode tables.
Clicking in space when a connector is selected adds the presynaptic node,
which is sent to the "Isolated synaptic terminals" group.

This facilitates the work flow with shift+alt to create connectors
for which the selected node is postsynaptic, and also ensures
that the isolated nodes created exclusively to be presynaptic placeholders
to the connector are stashed away under the "Isolated synaptic terminals"
group rather than left clutering the user's staging folder.