Introduces 'dist-bikeshed' target, removes dependency of 'buildonly' target on
bikeshed directory.

Patch by: amitmanjhi
Review by: rjrjr, fabbott


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@7862 8db76d5a-ed1c-0410-87a9-c151d255dfc7