Add a git pull check
fix quoting and simplify upstream reference check

Closes #19
Use `command` for git and silence `git fetch`
fix mangled prompts. closes #30

1. error message printed when no configured upstream branch
2. 256 color code used in precmd doesn't work on my terminal
3. preexec hook mangles output when the command itself contains escape sequences
4. cursor position isn't restored correctly when you have already began typing something before the async command executes
Use a lighter gray. Fixes #13
use more standard ansi+csr escapes. Refs #30
Merge pull request #31 from kouk/ansi-escapes

use more standard ansi+csr escapes. Refs #30
Don't show pull indicator when ahead of remote
Merge pull request #34 from alanpearce/patch-1

Don't show pull indicator when ahead of remote
Conditionalise git pull check

Whilst a nice feature, firing off a `git fetch` (and so an SSH/http call) after
*every* shell interaction is a bit heavy for my liking. This adds the ability to
disable it (whilst keeping it enabled by default).
Use arithmetic evaluation to test git pull flag

Closes #37
Add instructions for oh-my-zsh usage. #40
Prevent `%` from showing on unfinished lines
Close GH-41: Add integration with antigen.. Fixes #16
describe pure.zsh-theme
Add notes about user install and prezto to readme
Merge pull request #44 from sindresorhus/pb-doc-updates

Add notes about user install and prezto to readme
Close GH-45: Fix antigen theme integration..
Humanize the execution time. Fixes #46
Fix minutes typo in human_time()