Includes fixes for a number of DataForm and Thingy issues, as well as adding web APIs to make it easier to interact with WebGUI through code remotely.

Gotchas:

 * WebGUI now requires Class::C3 version 0.19 or greater.

Changelog:

 - changed: the list of extensions for the export system to pass through
   unmodified has been moved to the configuration file under the
   "exportBinaryExtensions" field.
 - fixed: some default assets have ids shorter than 22 characters
 - fixed: failure when submitting a dataform that sends mail with an empty file field
 - fixed: DataForm ignores height on textarea fields
 - fixed: DataForm doesn't keep posted values properly when data fails validation
 - fixed: Documentation for DataForm and Thingy updated for Possible Values field
 - added a new permission denied page for version tag approval
 - fixed: Thingy list type form elements do not support key/value pairs (SDH
   Consulting Group)
 - rfe: enable/disable pagination in asset manager  (#756)
 - Added Comments asset aspect, which allows comments to be added to any asset
   easily.
 - Added comments aspect to wiki.
 - Removed cart icon from ViewCart macro.
 - Added a basic auth mechanism to WebGUI, which will allow WebGUI to handle
   authenticated web service queries.
 - Updated WebGUI::Shop::PayDriver::processTransaction() to accept a
   transaction as a param.
 - fixed: Select Slider borked in Thingy (SDH Consulting Group)
 - fixed: Shortcuts includes HTML head data twice 
 - fixed: DataForm entry table isn't properly indexed
 - fixed: DataForm can't export fields containing newlines
 - fixed: UserList templates use incorrect variable names
 - fixed: International characters in password prevents login
 - fixed: SelectSlider form control is broken
 - fixed: testEnvironment.pl can't find WebGUI modules after installing a prerequisite
 - fixed: Combo box does not show possible values in Thingy (SDH Consulting
   Group)
 - Added some web services to the Gallery asset to support the use of remote
   apps to post photos and create albums.
 - fixed: Cross site scripting issue on operation pages
 - fixed: Search asset shows blank page after searching
 - rfe: Updated Thingy's edit instructions and search description fields to
   HTMLAreas (SDH Consulting Group)
 - rfe: Thingy Private Rows (SDH Consulting Group)
 - fixed: Shop: Percentage of Weight Shipping Method doesn't work
 - fixed #8776: duplicate does not duplicate keywords
 - rfe: Thingy: export extra rows, meta data (SDH Consulting Group)
 - rfe: Thingy: Max entries per user (SDH Consulting Group) 
 - Added the Asset Discovery web service content handler.
 - fixed: #4174: UserList template show links that should be hidden (Yung Han
   Khoe)
 - fixed #8802: isImage not functioning in Folders
 - added RFE #480: Apply button for assets
 - fixed #8807: _NewAsset.skeleton out of date
 - added: "Duplicate this template and edit" now updates the asset we came from, if any
 - fixed #8818: Visitor sends a welcome message
 - added: "EditArea" code highlighter and editing tool for WebGUI::Form::Codearea, used
    in Template, Snippet, SQLReport, and more
 - fixed: email password recovery allows sending recovery mail to arbitrary address