Aiger parser.

Appears to work for pre-1.9 formats, but not the updated format.
Added support for parsing bad state properties.
Made aiger model checker out of pcheck.

It appears to give wrong answers. Next step is to test it.
Removing pcheck, as it's now part of modelcheck.
Fixed bug in aiger checker.

The property being checked was accidentally inverted.
Output witnesses in proper format.
Added command line switch to select SMT solver.
Accept multiple files on the command line.

This makes it easier to profile a bunch of tests all in one batch.
Added scripts to make performance plot.
Added support for integer left and right shift.
Update performance gathering.
Updated test status based on improved implementation of smten.
Updated todo.
Updated performance gathering.