switches omnibus bootstrap script to use rubygems to determine Chef version
Update README.md

Add gem version badge
Switches to just unsetting GEM_HOME & GEM_PATH as done in PR #26
Merge pull request #34 from ctaintor/modify_bootstrap

Unset GEM_HOME & GEM_PATH in omnibus script
Update README.md
readme mentions that vagrant up can read from gusteau.yml
improving readme section about the gusteau vagrant plugin's interaction with .gusteau.yml
Merge pull request #35 from nicholasf/master

readme mentions that vagrant up can read from gusteau.yml
Fix README typo
Pass active node name into ENV for hook commands
Merge pull request #36 from anicholson/pass_node_to_environment

Pass active node name into ENV for hook commands
More verbose list from `gusteau list`

eg.
```
Known nodes are:
 - staging-vm (root@192.168.1.15)
 - production-db (billy@db.myapp.com)
 - production-www (billy@www.myapp.com)
```
Merge pull request #39 from locomote/verbose_list

More verbose list from `gusteau list`