[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.

[entities/wfobjs] add missing `DBG_SEC` debugging informations and a new `transition` capability

[warnings] put an end to warnings in the sqlite driver over `str` being sent instead of unicode strings

[web/request] clearly mark user_callback-related methods as deprecated The deprecated decorator not only emits a warning at run-time but above all makes the deprecation immediately apparent in the source. closes #3567793.

[book] document __unique_together__, remove bad RQLUniqueConstraint example RQLUniqueConstraint should be avoided whenever possible. Related to #3753250.

[schema] stop using RQLUniqueConstraint (closes #3753250) The last uses are replaced with unique together constraints.