If you install for instance EPiServer CMS Core libs from EPiServer NuGet feed (http://nuget.episerver.com) code documentation files (e.g. EPiServer.xml) is coming as well. Just be sure to copy over to bin/ dir if missing to get VS IntelliSense over thoses types.
Not sure about Mediachase.
This was supplied for EPi 6 a few years ago: http://world.episerver.com/Blogs/Enes-Bajramovic/Dates/2010/4/EPiServer-CMS-6-XML-documentation-files/
It would help a lot if our developers could get access to the same thing for Epi7, and preferably the mediachase dll files as well.
Thanks in advance.