New features and bug fixes in portal / system admin screens

- Aggregation Alias Admin
     - added validation on the new alias code
     - aggregation selection is now a drop down select box, rather than free text field
- Default Metadata Admin
     - added description field to allow users to enter more information about a set
     - added a userid field in the database, so we can have user-specific sets, as well as existing global sets
     - global default metadata sets are now cached in the application cache gateways
     - corrected issue deleting an existing default metadata set
     - corrected design issues when editing an existing default metadata in metadata editing screen
     - improved validation on the new data and better handing of invalid data
- IP Restriction Admin
     - added ability to delete an existing IP range grouping ( hide really )
     - improved validation on the new data and better handing of invalid data
- URL Portals Admin
     - default aggregation is now a drop down select box, rather than free text field
     - portal name added to the table of existing URL portals
     - portal name and URL segment must now be unique
     - improved validation on the new data and better handing of invalid data
- Web Skin Admin
     - base web skin is now a drop down select box, rather than free text field
     - corrected issue creating a new web skin due to deprecated 'zoomable_controls' folder
     - improved validation on the new data and better handing of invalid data
- Wordmarks Admin
     - corrected upload and delete issues
     - improved validation on the wordmark code
- Users & Groups Admin
     - corrected some text, which I had replaced errantly during code reorganization
     - more and better handling of nulls
     - viewing user groups now works again
     - some minor usability issues remain - will work on shortly

- Templates ( no actual admin screen at this time )
     - added description field to allow users to enter more information about a template
     - templates are now cached in the application cache gateways
Merge branch 'master' of github.com:MarkVSullivan/SobekCM-Web-Application

Conflicts:
	SobekCM_Library/AdminViewer/User_Group_AdminViewer.cs
	SobekCM_Library/AdminViewer/Users_AdminViewer.cs