BibEdit: multiple improvements and features

• Application title renamed to Record Editor in public interfaces.

• Moved many functions from bibedit_menu.js to bibedit_engine.js. Wrote table of contents in bibedit_engine.js.

• Editing of a field is now initated with single mouse click.

• Editing is now ended by clicking ESC (cancel), Return (save) or Tab (Save and Next). The "Save" and "Cancel" buttons are removed.

• Menu slightly rebuilt, with img links for "New record" and "Clone record".

• Added more hotkeys, for recently added features. Updated admin guide.

• Use of highlighting when cloning records.

• Use of highlighting when saving new content.

• Fixed improper handling of tags with characters.

• Submission will be denied if record contains invalid XML characters.

• Private functions in bibedit_utils.py prefixed and moved to end of module.

• Pretty exception if simplejson is not installed.

• Lots of minor improvements and bugfixes.