Upgrade boxen gem to 2.7.0 with Yosemite support

... including dependency on Puppet 3.7
Upgrade puppet modules for Yosemite support
Merge pull request #664 from boxen/yosemite

OS X 10.10 Yosemite support
Speed up bootstrap by using checksums

We've been using this modified bootstrap here at GitHub for months. I've
neglected to extract it to the public repo, until now.

This uses a quick checksum of `Gemfile`, `Gemfile.lock`, binstubs, the
ruby version and bundler version to determine if bundling is
necessary. This is much, much faster than running bundler every time.

I've also included some of our other misc. changes, mainly to logging
output and some minor structural pieces.
Port over github's newer boxen auto-update code
Add linked docs about how automatic updates work
Update FAQ to ensure proper bundle --path
Merge pull request #680 from seanknox/master

Fix typo in FAQ
Update sync script to the latest from @dgoodlad

As gisted at https://gist.github.com/dgoodlad/34f429d1b84a471933d3, and
linked from https://github.com/boxen/puppet-homebrew/issues/60, this is
the latest sync script used by Github's our-boxen. It uses the newer
aws-sdk-core gem, and apparently actually works.
Merge pull request #686 from indirect/newest_sync_from_dgoodlad

Update sync script to the latest from @dgoodlad
just keeping it fresh
Merge pull request #687 from boxen/update-puppet-modules-and-gems

Update Puppetfile and Ruby Deps
Install NodeJS using `nodejs::version`

The latest major release of puppet-nodejs, removed the versions classes:

    https://github.com/boxen/puppet-nodejs/releases

Cc: @tarebyte, @rafaelfranca
Merge pull request #688 from johnsyweb/fix-site-pp

Install NodeJS using `nodejs::version`
Dots, not underscores!

Addresses #689
Merge pull request #690 from johnsyweb/fix-site-pp

Dots, not underscores!
Update puppet-git for security release of git

See https://github.com/blog/1938-vulnerability-announced-update-your-git-clients
Merge pull request #665 from boxen/speedup-bootstrap

Speed up bootstrap by using checksums
Merge pull request #666 from boxen/improve-auto-update-ui

Improve auto-update UI
Merge branch 'master' into fix_gid_issue

Conflicts:
	script/bootstrap