Task Adapter 1.5.0: Github and MantisBT support

Task Adapter 1.5.0 is ready for download.

This is a major release, which supports 2 new systems:

Github **and MantisBT**.</span></div>

New features**</div>
  • Proxy support
  • Microsoft Project: added support for "priority" field.</ul>
    Plus a lot of bugfixes and minor UI improvements. **Full changes list. </div>
    Tested with Redmine 1.2.2.devel.7885 , Atlassian JIRA 4.4.3, MantisBT 1.2.8, Github.com website.