New features:
- Supports non-MSBuild projects.
- Setting different properties for each project in a solution.
- Build can run in a worker process
- Builds multiple projects in parallel
git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/trunk@2694 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61