beautify message list and content

git-svn-id: https://svn.apache.org/repos/asf/james/hupa/trunk@1522261 13f79535-47bb-0310-9956-ffa450edef68
dynamical style tool bar

git-svn-id: https://svn.apache.org/repos/asf/james/hupa/trunk@1522262 13f79535-47bb-0310-9956-ffa450edef68
add enable tool bar buttons toggling event, with being related to issue #31

git-svn-id: https://svn.apache.org/repos/asf/james/hupa/trunk@1522263 13f79535-47bb-0310-9956-ffa450edef68