If you are looking to use Compass in your own project and need a version that compiles in Visual Studio 2013 using Web Essentials - download this copy of compass.
At the time of this writing the latest update to Visual Studio 2013 is RC 3. Also, if you want to use the nightly build of Web Essentials, you'll need this update.
At the time of this writing, Web Essentials is getting some pretty heavy updates every day. I don't recommend ever grabbing the nightly build of any product or plugin automatically, but in this case you'll want to use the latest features. Instructions with screenshots have been provided on the following page:
Compass hasn't changed a lot the past couple of months but if you desire the freshest copy possible, then head over to the Compass project on GitHub and download the latest release. Once you have the SCSS files imported into your project, you need to go through them one by one updating the @import references.
The Compass compiler basically knows where Compass files are located already so these URLs just work. But Web Essentials uses relative paths. So these paths need to be updated throughout the Compass project. EG:
|Compass Does This||Web Essentials Needs This|
|[email protected] "/compass/css3/shared"||[email protected] "shared"|