Remove zprezto submodule
Delete and trim some zsh config files
Add zsh-syntax-highlighting plugin
Add zsh-completions plugin
Fix prompt
Collect shell aliases in aliases.sh
Set some options
Save zsh history
Copy more snippets from zprezto

* Load url-quote-magic module.
* Use Emacs bindings.
* Source /etc/zsh_command_not_found if present.
Fix broken prompt
Split zshrc into separate files
Update ls aliases
Rename directory functions.d -> functions
Load rbenv if present
Initialize fasd if present
Add gfr alias for `git pull --rebase`
Add more git aliases from prezto

Source: <https://github.com/sorin-ionescu/prezto/blob/391bc405d0378d092937f62944390b79edb13ad9/modules/git/alias.zsh>
Update `git log` aliases
Minor updates to zshenv and zshrc
Merge branch 'remove-prezto'