Respect VAGRANT_DEFAULT_PROVIDER environment variable

Vagrant v1.2 and newer support setting the default provider with
`VAGRANT_DEFAULT_PROVIDER`.
Fix tailor errors
Configure tailor to actually check the code style
Allow to override Vagrant default SSH username
add rackspace support
Delegate to super in #converge unless :use_vagrant_provision is set.
Allow the vagrant guest setting to be set in the generated Vagrantfile (via the .kitchen.yml)
Merge pull request #20 from tmatilai/default-provider

Respect VAGRANT_DEFAULT_PROVIDER environment variable
Merge pull request #21 from tmatilai/tailor-config

Configure tailor to actually check the code style
Remove #jamie-ci notifications from .travis.yml.
Refactor Rakefile to add `rake quality`.
Merge pull request #24 from gildegoma/override_username

Allow to override Vagrant default SSH username
Merge pull request #25 from simplymeasured/add-rackspace

add rackspace support
Merge pull request #29 from keiths-osc/vagrantfile-guest-setting

Allow the vagrant guest setting to be set in the generated Vagrantfile (via the .kitchen.yml)
Added Sane Defaults!!

Allows for computed defaults for a select list of pre-determined
platforms.

Currently a .kitchen.yml file of the following would work:

    ---
    platforms:
      - name: ubuntu-10.04
      - name: ubuntu-12.04
      - name: centos-5.9
      - name: centos-6.4
      - name: debian-7.1.0

    suites:
      - name: default
        run_list:
          - recipe[something]
Whitespace.
Merge pull request #30 from opscode/compupted-defaults

Computed defaults
add some quotes around Vagrantfile value
Merge pull request #31 from albertsj1/vbox_customize_missing_quotes

add some quotes around Vagrantfile value
Depend on test-kitchen ~> 1.0.0.beta.1 for upstream change.