ESX Maintenance Mode

Ensurable puppet resources that supports:
- entering MM
  - optional timeout (defaults to no timeout)
  - optional evacuation of powered off VMs, requires virtual center
- exiting MM
  - optional timeout (defaults to no timeout)
Merge pull request #94 from dscherer/maintenance_mode

Maintenance mode
test suffix to enable reuse as command
Merge pull request #95 from rbbrown/tb/mmelelel

demonstrate suffix to enable reuse of resource as command