Update vim config

Add:
+ Bundle: Vim-nerdtree-tabs
+ Bundle: Vim-Signify (Git diff in SignColumn)

Modify:
* Bundle: Use cutom solarized scheme

Remove:
- Bundle: Vim Git Gutter (better alternative)
Update zsh config

Add:
+ Alias for mvim
+ Enable osx, fasd, and ssh-agent modules in zprezto

Modified:
* Change editor variable to vim
Initial osx setup file

Add:
+ OSX preference setup script
Initial Iterm2 config

Add:
+ iterm2 preferences file
Source local .zshrc file if it exists

Modified:
* Have zshrc source ~/.zshrc_local.zsh if it exists.
Initital brew setup file

Add:
+ Homebrew initial setup file, not really tested..