Replace oh-my-zsh with prezto

Prezto claims to be a fork of oh-my-zsh but faster. I figure it is worth
giving it a spin.

For this commit, I am checking it in with the basic configuration. I
expect to make some modifications shortly.
Migrate .zlogin to .zshrc

Since I am moving to prezto, I may as well take this opportunity to
organize things a bit better. This commit breaks up my .zlogin file into
two separate files, functions and aliases, that are sourced by .zshrc.
In the process, I tweaked my aliases a bit to remove ones I never use.
Move path file from .shells to shell

Since I have the shell directory autoloading, this means I can remove
the line that loads this file.
Source .zshrc.local if it exists

This allows me to easily have a local configuration for zsh if I want
to.
Reorganize .zshrc

Just moving some things around to keep it more orderly.
Add .zpreztorc

This is the original configuration that came with prezto. I intend to
make changes to it but I wanted to be able to have a history of what I
did.
Customize .zpreztorc

Enable some modules and set some settings to my liking.
Ensure that submodules are recursively updated

Now that I am using prezto, which relies on submodules to stay updated,
I need to recursively update submodules when updating. This commit adds
these to my management scripts.
Commit binary vim spell file

I had updated the plaintext one earlier but neglected to commit this
file.