Add oyente, smartcheck, and octopus to bug finding tools

[brandongilchrist]

No description provided.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
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[dguido]

Thanks! However, we are only adding tools that we recommend (e.g., not Oyente) and tools that are open-source and that users can download for free.

I think you may also be working off an old branch? Can you sync to the latest master?