Add irssi configuration

- You will need to manually symlink ~/etc/irssi to ~/.irssi and
  manually copy ~/.irssi/config.example to ~/.irssi/config in order
  to use this configuration.
- It's mostly here to show which plugins I use and how I structure
  my IRC config, and not really meant for normal use.
Ignore files in irssi that may have passwords.
Fix git to-master and add git delete-branch.
Ignoring these were causing major problems in `gmt`.
Some improvements on OpenTestAlternate() in Vim.
Add an easy alias for the Email reader.
Fix $PYPATH so we can use httpie again. :)
Add global alias for `sudo $EDITOR`
Update `garc` to run `git clean -f` beforehand.

Not running `git clean` was just causing too many problems all over
the place. Now that we're forced to clean the repo before a
`rebase --continue`, we can ensure that no .orig or other mergetool
shit files will be hanging around our Git repos..
v0.6.0: $PATH fixes, git.plugin updates and irssi

- Add irssi configuration for communicating on IRC in a uniform
  manner. Connects to an irssi-proxy on psychededeli.ca in order
  to bridge onto the Freenode and Flowdock IRC networks. IRC is
  the preferred method of instant message communication due to
  its portability and extensibility, and irssi fits that
  description like a glove.

- Fix $PATH issues with Ruby and Python that were preventing the
  use of `http` for a while (httpie). Now that all of that has
  been resolved in $PYPATH, you should be able to use the `http`
  binary to query HTTP resources on the web.

- Improvements on `OpenTestAlternate()` in Vim include compliments
  to vim-vroom by switching between the test and implementation
  code of a given class. Still not *fully* functional with Minitest
  yet, but one day.