Don't build android modules from the top level; they're not really supported by Android yet as build artifacts

git-svn-id: http://zxing.googlecode.com/svn/trunk@2930 59b500cc-1b3d-0410-9834-0bbf25fbcc57
Pull common dependencies up into parent

git-svn-id: http://zxing.googlecode.com/svn/trunk@2931 59b500cc-1b3d-0410-9834-0bbf25fbcc57