Name conventions, Subheader, Subfooter, Cleanup, Drag'ndrop, Taxonomies

* Renamed nxs_404_pageid to nxs_404_postid
* Sitemeta home_pageid to home_postid
* Post's meta footer_pageid to footer_postid
* Added Subheader, Subfooter
* Post's meta header_pageid to header_postid
* Pagetemplate became a taxonomy instead of key/value of metadata
* When creating a new blog post, the wizard assists with dropdownlists
of subheader and footer too
* Improved drag'n'drop clearity of what containers the droppable areas
represent (shows containertyped in rows)
* Taxonomies are hidden in the admin GUI
* Revmoed wordpresstitle from widgets list
* Dragging now inserts a class to the html root DOM element
* Added a nxs_js_nxsisdragging variable indicating if a drag occurs
(true) or not (false)
* Pressing ESC while dragging no longer toggles the flyout menu
* Widths of various elements is no longer derived using jquery; uses CSS
(width 100%) instead
* Heights of specific nxs-XYZ-cursors is no longer calculated as there
no longer are cursors
* Scaffolding rows now show type of row (for example "Drop row
(subheader)")