Update README.md

Some wording changes and fixed markup for the link to the rspec-system-puppet gem.
Merge pull request #5 from ustuehler/patch-1

Update README.md
Include vsphere support

This adds a new node_set driver 'vsphere' for running test nodes on a vsphere
cluster. This has been tested against VSphere 5.1 specifically.

Signed-off-by: Ken Barber <ken@bob.sh>
Add default_node to kwalify schema

Signed-off-by: Ken Barber <ken@bob.sh>
Some cleanup

Signed-off-by: Ken Barber <ken@bob.sh>
More ignores for git

Signed-off-by: Ken Barber <ken@bob.sh>