Set the upload directory at the formitem level

Require the upload directory to be relative to the root, and add error
checking to enforce it.
Fix upload directory error checking

- show errors in the form instead of breaking it

- correctly check if directory exists and is writable
Fix error when $config['forms'] key is not the same as the database name
Fix Notice, Strict, and Deprecated errors when running in PHP 5.4
Remove old and unused admin files
Remove the 'sprite' button option

The 'sprite' button is not used enough to warrant updating it to work with
the new structure.
Allow captcha to work with custom session names
Replace instances of the deprecated split() function
Allow setting the number of characters in the captcha
Merge branch 'captcha' into restructure
Remove 'Date Picker' code

'Date Picker' can be easily added via javascript if needed, therefore it
shouldn't be in this code.
Remove unused global variables
Remove 'WYSIWYG' code

'WYSIWYG' can be easily added via javascript if needed, therefore it
shouldn't be in this code.
Make sure variable is set before appending to it