git-svn-id: http://google-refine.googlecode.com/svn/trunk@74 7d457c2a-affb-35e4-300a-418c747d4874
Allow expressions to be evaluated on null cells too. Various minor UI polishing touches and minor bug fixes. git-svn-id: http://google-refine.googlecode.com/svn/trunk@58 7d457c2a-affb-35e4-300a-418c747d4874