tat command now works in directories with periods

- Running `tat` in the robots.thoughtbot.com directory was throwing a
'bad session name' tmux error
- See http://sourceforge.net/p/tmux/tickets/109/
Set Vim's spellfile to $HOME

Running `zg` adds words to the `spellfile`:

https://github.com/thoughtbot/dotfiles/commit/4f5a2edc336970b8a1c7eded3934182810abeb20
http://robots.thoughtbot.com/vim-spell-checking

Setting the spellfile keeps it out of its default location, `vim/spell`, which
would otherwise be inside thoughtbot/dotfiles. We don't necessarily want to
share the `spellfile` across the team.
Update for Vundle's new interface

* Vundle now lives at gmarik/Vundle.vim

See https://github.com/gmarik/Vundle.vim/blob/master/doc/vundle.txt#L345-L369
Make it easy to checkout GitHub pull requests

This alias makes the following workflow possible:

Look at changes:

    git co-pr 123
    git diff origin/master

Bundle, validate tests are passing:

    bundle
    rake

Rebase interactively, squash, and potentially improve commit messages:

    git rebase -i master

Merge code into master:

    git checkout master
    git merge pr/123 --ff-only

Push:

    git push origin master

Clean up:

    git branch -D pr/123
Allow personal overrides to psqlrc

I wanted to add my own customizations after reading @mike-burns' post on
[`psqlrc`](http://robots.thoughtbot.com/an-explained-psqlrc).

As a result of this change, `.psqlrc` requires that a `.psqlrc.local`
exist in the home folder because `psql` cannot do conditional sourcing
of files in the style that we use in other foundation dotfiles. Touching
the file to ensure it exists (even if blank) prevents `psql` from
exiting with an error if the user does not provide their own custom
configuration.

Additional changes:
* Updating the documentation with regard to which files get excluded.
Improve ag tab completion

* Remove unnecessary `uniq`
* Look for tags in tmp/tags or .git/tags
* Send errors to /dev/null if the file(s) do not exist

See http://tbaggery.com/2011/08/08/effortless-ctags-with-git.html for an
explanation behind the reasoning for .git/tags.
Add vim-multiple-cursors plugin for Vim
Revert "Add vim-multiple-cursors plugin for Vim"

This reverts commit 422a6f6d3324a7c6060793657054025d41a7bab3.

Want to go through a PR cycle.
\unset QUIET is case sensitive
Introduce ~/.zsh/configs

Just before loading `~/.zshrc.local`, load:

1. `~/.zsh/configs/pre/**/*`
2. `~/.zsh/configs/**/*` # excluding pre and post
3. `~/.zsh/configs/post/**/*`
Update the README
Replace find with zsh glob

Breakdown:

- `.`: only produce normal files.
- `-`: follow symlinks to their final file; skip any broken links.
- `N`: do not complain about zero matches.

Big ups to @pbrisbin for finding `N`.