Change Berkshelf#vendor method signature to match master branch

options no longer passed to #vendor and instead part of initializer
Merge pull request #147 from berkshelf/fix-vendor-signature

Change Berkshelf#vendor method signature to match master branch
bump required berkshelf version
Minor comment clean up
Merge pull request #150 from jjshoe/patch-1

Minor comment clean up
Added info about Vagrant 1.5 Compatibility

To avoid issues about the plugin not working on 1.5
Merge pull request #157 from Grafikart/patch-1

Added info about Vagrant 1.5 Compatibility
Fix for Vagrant 1.5

- Drop support for Vagrant < 1.5
- Drop test for Ruby 1.9.3
- Remove usage of config_global
- Fix UI initialization
Specify Vagrant 1.5.x
Merge pull request #158 from chulkilee/vagrant-1.5

Fix for Vagrant 1.5
add self to plugins group in Gemfile for plugin development
version bump 2.0.0.rc1
bump required berkshelf version
bump version 2.0.0.rc2
update install instructions on readme to pull in release candidate

this should be removed when we go live with Berkshelf 3.0
remove @author tag. This isn't part of our coding style anymore
remove the tested vagrant version check

I trust the plugin system in Vagrant now
Merge pull request #162 from berkshelf/remove-tested-requirements

remove the tested vagrant version check
Use recommended download URL
Merge pull request #164 from goatherd/patch-1

Use recommended download URL