Account for stopping states when determining existing vas

vms may be in the stopping or destroyed state should
not be treated as present.
update instance property hash

so that subsequent objects can inspect it.
Add key pair as instance property
add uesrdata as instance parameter
chmod of cached private keys

to 600 so that ssh will use them by default
do not fail if there are not network

just adds some extra checking to prevent nil
exceptions when there are no networks defined.
do not fail if there are no key pairs

Adds extra error checking to prevent failures
when there are not key pairs defined.
do not set property_hash to resource in flush

b/c some of the properties being set are not set
in the resource, but parsed from the creation
response.
add error checking when key file is searched for.
Expand puppet_node resource

This resource supports installing puppet
enterprise, and classifying agents.
update example manifest

to demonstrate creation of supported objects.
remove commented out key pairs

cleans up some commented out code, fixes formatting
allow key pairs to be wither references or strings

so that you can refer to previously created key pairs.

also, ensure that any specified key pairs are 
auto-required.
Add exists method to keypair