Added ability to start and stop existing EC2 instances.
Add rule group_name parameter whose value can reference containing group name.
Check for group_name and cidr_ip.
Added the ability to add volumes to instances at creation time

This allows a volume to be cloned from a snapshot, a brand new
volume to be created, or an ephemeral volumes to be associated
at time of instance creation.

This avoids any race conditions associated with creating extra volumes
after instance creation (e.g. writes happening before the volume is
mounted).

In addition, this allows the root volume to be edited
Fix exception being thrown for new instance

Currently if we are trying to register an instance that has not yet
been registered with the elb an exception is thrown.
Merge pull request #4534 from willthames/ec2_mount_volumes

Added the ability to add EBS volumes to EC2 instances at creation time
Fixing traceback caused by incorrect argument passing to json.dumps

Fixes #5756
Merge pull request #5783 from jimi-c/issue_5756

Fixing traceback caused by incorrect argument passing to json.dumps
sysctl: parse bool value as 0/1 and refactor a little bit
Merge pull request #5380 from dhml/devel

ec2_group: rules can't reference containing group fix #5309
Merge pull request #5787 from jirutka/fix-sysctl-bool

sysctl: parse bool value as 0/1 and refactor a little bit
Merge pull request #5506 from mohangk/fix_elb_register_new_instance

Fix exception being thrown for new instance registration with ELB
Allow su_user to be templated, same as sudo_user.
Fixing bug relating to su without an su_pass
Merge branch 'feat/ec2_start_stop' of git://github.com/Geryon/ansible into Geryon-feat/ec2_start_stop
Fix start/stop example in ec2
Add skip_tags to ansible-playbook man page
Merge pull request #5793 from garaden/skip_tags

Add skip_tags to ansible-playbook man page
Micro-optimization of inventory.expand_hosts.detect_range
Micro-optimization: replace s.find(x)!=-1 with x in s

timeit shows a speedup of ~3x on Python 2.7.5 x86_64.
It also makes the code a bit shorter.