Adding a TokenValue to CssProperty to handle CSS components that should not be wrapped with spaces.  This fixes a bug in the generated css for WidgetUiDemo that affects IE.

Patch by: jlabanca
Review by: bobv



git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@6458 8db76d5a-ed1c-0410-87a9-c151d255dfc7