Update to a newer version of sbv

This one works with newer releases of z3.  No code changes required, luckily.
Update the library interface parsing code (and aeson version)

The old library interface parser relied in the generically-derived JSON
parser from aeson.  Unfortunately, the format that aeson used for these
parsers changed in 0.7.  Instead of updating all of the data, we now use
manually-written ToJSON and FromJSON instances.  We can now safely use
modern versions of aeson.