Include gitconfig.local file for personal changes

* assumes same directory existance
* allows for easier addition of personal configs
Source ~/.zshrc.local if it exists

Follows the pattern of:

* ~/.aliases.local in ce7ad49
* ~/.gitconfig.local in 8e141fe
* ~/.vimrc.local in a666267

Use consistent:

* `source`ing style.
* commenting style.

I am using ~/.zshrc.local as a home for `eval "$(rbenv init -)"`.
Git push to current, not upstream

The primary use case for me is to `git push staging` and `git push
production` from the master branch using our typical git workflow:

https://github.com/thoughtbot/guides/tree/master/protocol#deploy
Make the migrate alias faster

This was loading up the environment four times when it really only needs
to happen twice.
Remove unused vim plugins

* haml, html and markdown highlight still work without these plugins
* treetop and textile are likely very situational
* unsure if anyone is using greplace
Remove old ignores

* sass gets compiled to `tmp/sass-cache` with Rails
* vendor/bundle_gems seems like an arbitrary vendor directory
* vim/.netrwhist is for a plugin we no longer use
List local files available to override
alias goodmorning
Use sublime over vim (for now)
Personalize git username and email.