Compatibility with habitat-sim#6 (#46)

* Made simple agents suitable for challenge submissions.

* Addressed the comments, chaned flag names, switched to benchmark

* Removed .swp file, added swp to gitignore.

* Compatability with habitat-sim#6

* Fix formatting

* Just use the quats to rotate thing

* Burn in looks good

* Fixup newly merged code wrt. this PR

* Nits

* Fixup quaternion usage

* Add TODO