Code Maintenance: Less/CSS style fixes
Review Request #3027 — Created March 28, 2012 and submitted
Less/CSS style fixes:
Replace "0px" with "0" where applicable
Changed ".6em" to "0.6em" in admin.less
Made use of definitions in defs.less
imported defs.less into common.less
Added -webkit rule to .border-radius definition
Added .border-shadow definition
Made use of .border-radius where applicable
Visual inspection on local machine: Ubuntu 11.10, Chrome 17
