Merge pull request #1 from elinw/davidsbranch

Further UCM Work
Updated to use primary key for Type lookup
Updated to have BaseUcm and UcmContent extending UcmBase
Cleaned up code, simplified functions
Merge branch 'ucm' of https://github.com/davidhurley/joomla-cms into davidsbranch

Conflicts:
	libraries/cms/ucm/base.php
clean up some typos