Update 1 shipped with the ability for customers to run the Roslyn IDE
bits live in Visual Studio without doing unnatural things to their
machines. We produced the final build before we got all the code changes
needed in the branch, so we had the update-1 branch as a branch that
contained what we shipped, plus the extra stuff they would need. This
all was merged in and included in master for update 2, so at this point
this branch can go away.