Update copyright year
Export modelAssocs

Only thru internals though. Can come in handy for further user-level
programming.
Update year
Simplify allSat implementation, addresses #78.
Record recent changes..
Implement allSat for uninterpreted sorts

The idea is to use equivalence classes as identified by the backhand
solver to reject satisfying models. It was Eric Seidel who suggested
the idea, see #80. Thanks!
allSat: generate unique file names

if smtFile option was given, we were overwriting the file over and over
for each call. Add an index to the file-name to avoid this.