Fix for bug 444, dealing with the placing of set-logic in dumping modes.

Fix for bug 444, dealing with the placing of set-logic in dumping modes.
CVC4 now produces equivalent output when dumping the SMT1 and SMT2 attachments to that bug report.

This also fixes a memory leak in the new-variable-notification mechanism.

(this commit was certified error- and warning-free by the test-and-commit script.)