Adding support for specifying loop/recursion unroll bounds about symbooglix

[delcypher]

@zvonimir I should have some time this week to take a look at this.

[zvonimir]

@delcypher I noticed you've been playing with symbooglix recently (thanks!), and so maybe you could take a look at this issue as well. Thx!

[delcypher]

@zvonimir Yes sorry. I haven't forgotten this issue but it's been hard to find time to look at it. I'm trying to fix failing tests right now. The test pass on my machine™ but don't seem to pass in TravisCI. Once I get the tests working again I'll hopefully find some time to implement the loop bound.

[delcypher]

@zvonimir I've now implemented support for a loop bound. This supports nested loops. The loop bound is off by default but can be enabled with the new --max-loop-depth= flag.

Sorry this took so long. I've been very busy with paper deadlines until recently. This feature also required quite a bit of thought to get the design right.

There may be bugs in the implementation because it hasn't been heavily tested so please report any issues you hit.

[zvonimir]

Thanks @delcypher! We'll give it a try ASAP and let you know if we find any bugs.