Changed brew cmd to properly report if awscli is installed via homebrew
Added VIRTUAL_ENV_DISABLE_PROMPT to steeef.zsh-theme

This stops the virtual env name from being printed before it is actually being
used in the zsh prompt.
Merge simplified superjarin theme
Fix autojump script to support Nix installations
Fix Yosemite broken zsh where $PATH var does not get appended correctly.

Sourcing oh-my-zsh immediately after export PATH.
use pigz if available in extract plugin
Merge pull request #3309 from jarinudom/superjarin

Simplify superjarin theme and support chruby
Merge pull request #3283 from jaapz/master

Added VIRTUAL_ENV_DISABLE_PROMPT to steeef.zsh-theme
Merge pull request #3265 from thii/fix-yosemite-broken

Fix Yosemite broken zsh
Merge pull request #3092 from MWers/aws-brew-issue

[aws plugin] Changed brew cmd to properly report if awscli is installed via homebrew
Merge pull request #2871 from wrboyce/extract-pigz

use pigz if available in extract plugin
Merge pull request #2448 from gawashburn/master

Fix autojump script to support Nix installations
Refactor similar functions into common sections
Fix take function

Before the modification, the `take` function will try to cd
into the created directory even if mkdir throws an error.

With this modification, if mkdir fails to create the directory,
cd won't run and the take function will return the mkdir exit
code.