Add context supporting use with Eucalyptus.

- Add EucalyptusChaosMonkeyContext
- Add configuration of eucalyptus client properties

Example client.properties:

  simianarmy.client.aws.accountKey = 1CSDM1FT4G8ZKDZ1AZR2
  simianarmy.client.aws.secretKey = XXXXXXXXXXXX
  simianarmy.client.aws.region = us-east-1
  simianarmy.client.context.class=com.netflix.simianarmy.client.eucalyptus.EucalyptusChaosMonkeyContext
  simianarmy.client.eucalyptus.hostName = 10.111.1.119
  simianarmy.client.eucalyptus.accountKey = YRLWV7NSQK2FSXKCOTKET
  simianarmy.client.eucalyptus.secretKey = XXXXXXXXXXXX
  simianarmy.client.eucalyptus.region = us-east-1