Add support for tags parameter to cloudformation module

Expose boto.cloudformation.create_stack() tags parameter. Supplied tags
will be applied to stack and all it's resources on stack creation.
Cannot be updated later (not supported by UpdateStack CloudFormation
API).

library/cloud/cloudformation

@@ -60,6 +60,12 @@ options:
     required: true
     default: null
     aliases: []
+  tags:
+    description:
+      - Dictionary of tags to associate with stack and it's resources during stack creation. Cannot be updated later.
+    required: false
+    default: null
+    aliases: []
 
 requirements: [ "boto" ]
 author: James S. Martin
@@ -79,6 +85,8 @@ tasks:
       DiskType: ephemeral
       InstanceType: m1.small
       ClusterSize: 3
+    tags:
+      Stack: ansible-cloudformation
 '''
 
 import json
@@ -163,7 +171,8 @@ def main():
             region=dict(aliases=['aws_region', 'ec2_region'], required=True, choices=AWS_REGIONS),
             state=dict(default='present', choices=['present', 'absent']),
             template=dict(default=None, required=True),
-            disable_rollback=dict(default=False)
+            disable_rollback=dict(default=False),
+            tags=dict(default=None)
         )
     )
 
@@ -173,6 +182,7 @@ def main():
     template_body = open(module.params['template'], 'r').read()
     disable_rollback = module.params['disable_rollback']
     template_parameters = module.params['template_parameters']
+    tags = module.params['tags']
 
     if not r:
         if 'AWS_REGION' in os.environ:
@@ -203,7 +213,8 @@ def main():
             cfn.create_stack(stack_name, parameters=template_parameters_tup,
                              template_body=template_body,
                              disable_rollback=disable_rollback,
-                             capabilities=['CAPABILITY_IAM'])
+                             capabilities=['CAPABILITY_IAM'],
+                             tags=tags)
             operation = 'CREATE'
         except Exception, err:
             error_msg = boto_exception(err)