mod_editor_tinymce: fix problem where tinymce coulde be initialized with a non-supported language. Add 'do_zeditor' to initialize individual textareas with a fulltext editor.
mod_base: Remove usage of symlinks in jquery files

Fixes #812
docs: minor change for overrules docs.
core: prevent leakage of query args from one transport to the next. Ensure query validation.
core: use transport for moving the upload progress to the browser.
core: add some convenience functions to z_session_page for looking up session_id, stopping and checking attach state by context
core: poll the task queue by date, oldest task first.
core: set empty cookie list in dummy reqdata.
core: (transport) ensure that there is a valid session/page before handling postbacks.
core: better image quality for rendering PDFs
mod_survey: better survey results display.
core: only send a websocket ping if readyState is 1 (connected)
core: fix confusing indentation.
mod_admin_users: remove username/password buttons if not allowed to edit those.
core: Include ubf.js in blog skel.

Fixes #823
mod_survey: Align ACL check of printable results page
core: create custom pivot tables inside a transaction.
core: commit any changes from Module:manage_schema before handling the #datamodel. Not committing the the transaction locks the rsc table if a new fk constraint to the rsc table was created.
mod_editor_tinymce: initialize the tinyMCE editors lazily if they become visible.
mod_rest: prevent double quoting when importing backup files.