add xcode instructions for mavericks
Update script/bootstrap sudo to pass environment variables.

When executing a boxen run from inside the corporate firewall we need to pass
proxies through to sudo so that bundler will be installed properly as root.
Merge pull request #489 from johnbellone/patch-2

Update script/bootstrap sudo to pass environment variables.
update XCode instructions re: boxen-web
Merge pull request #485 from afeld/patch-1

Add XCode instructions for Mavericks
OSX -> OS X
Update README.md

I found a superfluous space, and also because you are _in_ the directories you need to `./script/boxen` each time.
Merge pull request #490 from jjasghar/patch-1

Update README.md
comment out old dependency versions of node, ruby
add chrome, iterm2, sublime text
add ignore cache
add init script
update setting
update apps
fix readline of ruby
update package
update init shell
change pow install way
modify comment
add nodejs stuff setting