mattdrayer/api-middleware-regex: Support for opaque keys, server API nam...

@chrisndodge @antoviaque, I think I've finally gotten to the bottom of the failing LMS tests.  In troubleshooting I went ahead and added the "server" namespace to the root URI as I mentioned earlier today.  So, @martynjames, FYI that you'll need to update Apros to reflect the new path (/api/server/courses, etc.) after this PR has been merged.

Chris and I discovered that the social metrics test fails due to a failed mock when running the suite via paver, however it passes when running via rake -- very odd.
For all these cases, in both migration scripts, when we couldn't make the conversion, it could be helpful to differentiate the cases (new-style key, other cases), and log it extensively. If we ever need to figure out what went wrong, that might be very helpful