Fix repo structure tree and update `aicrowd.json`

See merge request nethack/neurips-2021-the-nethack-challenge!17

This reverts commit f8425bfa

Dipam/updates

See merge request nethack/neurips-2021-the-nethack-challenge!15

Merge from Master

See merge request nethack/neurips-2021-the-nethack-challenge!14

Improve Torchbeast Baseline Instructions

See merge request nethack/neurips-2021-the-nethack-challenge!13

Fix TOC, change images, other minor changes

See merge request nethack/neurips-2021-the-nethack-challenge!11

# Conflicts:
#   README.md

Update README & Bugfixes

See merge request nethack/neurips-2021-the-nethack-challenge!12

First pass at improving README.

See merge request nethack/neurips-2021-the-nethack-challenge!8

Delete unnecessary utils.

See merge request nethack/neurips-2021-the-nethack-challenge!9

Fixup agents and remove reference to RLlib.

See merge request nethack/neurips-2021-the-nethack-challenge!7

Add Dockerfile for TB baseline.

See merge request nethack/neurips-2021-the-nethack-challenge!3