Fix for bug 555; SMT-LIBv2 symbols now output with proper quoting.
Set dumping options from (set-option..) and API more directly.
Refactor the theory specific parts of definition expansion into the theory solvers.

In the process of doing this I may have fixed some bugs or some potential bugs so there
may be some user visible results of this refactoring.

Signed-off-by: Morgan Deters <mdeters@cs.nyu.edu>