Fix Berkshelf integration

- Fixes #73
Whoops, passing parameters is good
Allow loading cookbooks from the Berksfile.lock file

I needed to promote a cookbook that was not part of the immediate Berksfile, but was in the Berksfile.lock as it was a dependency of a cookbook.
Raise error when no lockfile is found

@sethvargo should we keep track somewhere that this can be solved
differently in master?
Merge pull request #1 from RSO/patch-1

Allow loading cookbooks from the Berksfile.lock file
Use cookbook.path.to_s when the cookbook is a CachedCookbook
Merge pull request #2 from RSO/patch-1

Use cookbook.path.to_s when the cookbook is a CachedCookbook
Fixed -b option definition, which fixes jonlives/knife-spork#73
Merge pull request #3 from RSO/fix_berkshelf_option

This commit fixes jonlives/knife-spork#73
Merge pull request #74 from sethvargo/promote_berksfile

Fix Berkshelf integration