Add link to survey to our readme.
Add link to survey to our readme.

dbeyer/benchexec,sosy-lab/benchexec,ultimate-pa/benchexec,ultimate-pa/benchexec,ultimate-pa/benchexec,ultimate-pa/benchexec,dbeyer/benchexec,ultimate-pa/benchexec,sosy-lab/benchexec,sosy-lab/benchexec,sosy-lab/benchexec,dbeyer/benchexec,ultimate-pa/benchexec,sosy-lab/benchexec,dbeyer/benchexec,sosy-lab/benchexec