Started to work on supporting Vagrant 1.1+
Moved vagrant plugin classes to a dedicated folder v1
Initial support of vagrant v2 plugin system
Fixed user parameters command in vagrant v2
Updated gem file to conditionnaly load vagrant dependency
 * If VAGRANT_PLUGIN_VERSION is set, it will be used to decide which
   version of the plugin to use when developing with bundle install.
   Possible values are v1 or v2, defaulting to v2
Changed how plugin is loaded
 * Require 'nugrant' will need conditionally decided which version of the
   plugin to load.
 * An error message will be displayed if an unsupported version is
   used with a newer Vagrant.
Now ignoring Vagrantfile and added a bunch of test Vagrantfile
 * You can cp Vagrantfile.vX.something Vagrantfile to test a specific
   Vagrantfile setup
Bumped version to 1.0.0.pre1
Removed leftover debug traces
Updated changelog for release of version 1.0.0
 * It seems that it is not possible to install pre version of
   plugin within Vagrant 1.1.x
Bumped version to 1.0.0