Removed version specific information for Mono.Addins reference
Recent changes in the latest alpha of Xamarin introduced a dependency
on version 1.0.0.0.  Its really a version neutral file so there is no
need to bind to a specific version as the F# binding will be deployed
with a dependency on a specific version of MonoDevelop/Xamarin Studio.
Merge pull request #199 from 7sharp9/master

Removed version specific information for Mono.Addins reference