Merge pull request #1 from rotaris/master

SQL statement unquoting and removed reference to non-existent class 'Concept'
Merge pull request #2 from rotaris/master

GD/Image Rendering of HTML Entities
ADLDAP changes. General commenting additions
ADLDAP v4
Update of Readme to include basic install instructions
Small form update
Added Debugging capability for Exception. Added OSX support for compiling questions
Tidied up Question Generation screen a bit
Allowed editing of quiz concepts
Added a database profiler function that can display database query execution times etc in the footer. Used for debugging.
Turn off debugging in attemptAction() in ShellController.php. Also added an extra line of debugging output too.
Code lines smaller than 2 characters long (but at least 1 character long) now appear in the rendered image.
Increased the `permissions_group` field’s max size (because some group names could be large).