Write heuristics to output file

[elig0n]

This appends 'heuristics' dict to the saved JSON

[s0md3v]

Hey @elig0n, thanks for the bug fixes, I merged them all.

However, the parameters found by heuristics aren't intended to be save to the output. Arjun verifies those parameters and includes them them in params object in the JSON output. The only thing that should be fixed here is that the initialize function shouldn't return the found variable.

I am closing this for now but open for discussion.