Important
Effective with this release, Visual Studio 2010 and Visual Studio 2012 are no longer supported. With the release of Visual Studio 2015, I needed to reduce the number of versions for which I can realistically provide support. Four versions was starting to be too many.
If you need spell checking support for those versions, you can download the v2015.3.1.0 release and install it. Most of the recent bug fixes have been related to changes in Visual Studio 2013 and Visual Studio 2015 so the prior release is quite stable.