Remove unused addins.
Add dependencies for MD 3.0 and MD 4.0.
Add support for multi-version.
Add other dependencies.
Add conditional part for API change.
Merge commit '0e6f62e61235f23109058b6571875af748d91e2a'
Parametrize the build to support MonoDevelop 3.0 and 4.0.
Closes #8.