Add several usability patches to nethack

Nethack.alt.org is widely seen as running the best version of Nethack around, but high latency impacts the experience.  This commit alters the version of nethack used by homebrew-games to incorporate the patches used by nethack.alt.org including
* [Menucolors](http://bilious.alt.org/?11)
* [Statuscolors](http://bilious.alt.org/?142)
* [Sortloot](http://bilious.alt.org/?42)
* Over 20 bugfixes
* And quite a few more (see [my fork of NAO's nethack](https://github.com/ffleming/nethack-3.4.3-nao-osx/blob/v1.0/README.md) for more information)

This version also compiles in a a few options that are available but disabled on a standard Nethack install:
* `DLB` for a cleaner install (ie there are fewer files hanging out in `/path/to/cellar/libexec`),
* `SHELL` so that a player can type `!` to drop to a shell
* `AUTOPICKUP_EXCEPTIONS` to make autopickup more configurable via `.nethackrc`