feat(contrib/ec2): add m3 instances to template

The current generation of EC2 instances (M3) is faster and cheaper
than the old M1 instances. It's a more reasonable default to use
m3.medium as the default instance size.

fixes #689

Author: Matthew Fisher

contrib/ec2/deis.template

@@ -33,8 +33,8 @@
     "InstanceType" : {
       "Description" : "EC2 instance type (m1.small, etc).",
       "Type" : "String",
-      "Default" : "t1.micro",
-      "AllowedValues" : [ "t1.micro","m1.small","m1.medium","m1.large","m1.xlarge", "m3.xlarge", "m3.2xlarge", "m2.xlarge","m2.2xlarge","m2.4xlarge","c1.medium","c1.xlarge","cc1.4xlarge","cc2.8xlarge","cg1.4xlarge", "hi1.4xlarge", "hs1.8xlarge"],
+      "Default" : "m3.medium",
+      "AllowedValues" : [ "t1.micro","m1.small","m1.medium","m1.large","m1.xlarge", "m3.medium", "m3.large", "m3.xlarge", "m3.2xlarge", "m2.xlarge","m2.2xlarge","m2.4xlarge","c1.medium","c1.xlarge","cc1.4xlarge","cc2.8xlarge","cg1.4xlarge", "hi1.4xlarge", "hs1.8xlarge"],
       "ConstraintDescription" : "must be a valid EC2 instance type."
     },
     "ClusterSize": {