Release 2.5.1

Release notes and gemspec changes for release 2.5.1.

Signed-off-by: Ken Barber <ken@bob.sh>
remove unnecessary if statment

- remove if statment (will be true/false anyway)
- remove trailing space
- remove systemu assigment to result variable (never used afterwards)
Merge pull request #66 from JHaals/skipif

remove unnecessary if statment
fix multi-node sample in readme
Merge pull request #68 from pall-valmundsson/fix-multinode-readme

Fix multi-node sample in readme
Refactor with some new features

* Split out vagrant commonalities into a vagrant_base class
* Add support for vagrant-vmware_fusion
* Fix vagrant so we log in as root, not log in as vagrant and sudo
* Break out steps in providers: launch, connect, configure
* Generalise the SSH connection routines
* Provide a series of global configuration steps, like ntp sync, hostname
  fixups etc.
* Deprecated the internal_helpers module, its better to avoid global
  methods anyway
* Switched to using RS_ as the prefix for environment variables

Signed-off-by: Ken Barber <ken@bob.sh>
Merge pull request #70 from kbarber/ticket/master/provider_features_and_refactor

Refactor with some new features
Release 2.6.0

Signed-off-by: Ken Barber <ken@bob.sh>
Merge branch 'release_260'

* release_260:
  Release 2.6.0