Wait for SSH connection after rebooting the machine

Ensure that the VM is accessible after we reboot it.
This also makes sure that the guest addition version is reported
correctly after upgrading.
Update Readme.md

Small typo fix
plugin definition should match the actual gem name
Merge pull request #93 from scalp42/patch-1

Fix typo in Readme
Merge pull request #90 from tmatilai/wait_for_ssh_after_reboot

Wait for SSH connection after rebooting the machine
Merge pull request #94 from scalp42/vagrant.has_plugin

Plugin definition should match the actual gem name
Fix release dates in Changelog

v0.6.0 and v0.6.1 where wrongly stated as released in 2012, but should be 2013.
Mention new wait for SSH in changelog
Mention new internal plugin name in Changelog