[wsgi] add tornado http server

[wsgi] add message about the active interface Similarly to what done in "stdlib".

[cwctl] rewrite wsgi method choices This will help devs to add new choices by adding their callback to WSGI_CHOICES. Note: ``options`` becomes a property because ``wsgichoices()`` should be evaluated at the last-minute.

[skeleton/debian] use dh_python2 instead of dh_pysupport for new cubes The former is deprecated.

[web] Add source for jquery.qtip.js Downloaded from https://github.com/Craga89/qTip1/raw/master/1.0.0-rc3/jquery.qtip-1.0.0-rc3.js Related to #3851121.

[web] Replace minified copy of jquery.flot.js 0.6 with non-minified version Related to #3851121

[web] Update jquery-treeview to the latest version Files copied from commit 61f230828ace1b54c2cc54bc549ece261b11842e of https://github.com/jzaefferer/jquery-treeview

[web/css] move jquery.treeview.css override to a separate file Patched embedded code copies are a maintenance disaster (even more so than plain embedded code copies). Let's not do that.

[web] Stop patching jquery.treeview.js This logically reverts part of e9b7cd2e9012 "allow treeview to work correctly in a tab #345293". The treeview and ajax code have suffered a number of changes since then, this change doesn't seem to be necessary anymore. It is most likely unneeded since f65208c9dbdc "[javascript] use jQuery.one('ajax-loaded') instead of jQuery.bind() in add_onload to avoid multiple callback executions".

[web] Beautify jquery.treeview.js Fully mechanical, just whitespace changes.