Use `brew.sh` instead of `Brewfile`

Also, remove `Caskfile` since I didn’t use it.

Closes #428.
.bash_profile: Support multiple hosts in SSH completion

Useful in cases such as:

```

Host vm1 vm2 vm3 vm4
     Host localhost
     # ...
```

Simply adding a `-` to `tr` fixes this.

Closes #437.
.vimrc: Enable `g:solarized_termtrans`

It improves the display in OS X Terminal.app.

http://ethanschoonover.com/solarized/vim-colors-solarized

Ref. #425.
brew.sh: Use `--with-iri` for `wget`

The older `--enable-iri` flag is deprecated.

Closes #445.
.exports: Remove `export HOMEBREW_CASK_OPTS`

It’s not needed anymore now that the `Caskfile` has been removed.

Closes #446.
.aliases: Remove npmjs.eu reference

See the deprecation notice: http://npmjs.eu/

Closes #448.
.functions: Make `mkd` `cd` into the last directory in the list

…rather than the first.

Closes #447 and #450.