changes to support getting vm status

Ref TheWeatherCompany/grid-api#509
create new pogo for vm status

Ref TheWeatherCompany/grid-api#509
fix spelling mistake
prate getVMStatus to take null value for vmIds

will return all vms if null
Ref TheWeatherCompany/grid-api#509
Merge pull request #41 from TheWeatherCompany/support-to-get-vm-status

Support to get vm status