Ec2 facts boto

Adds the option to get ec2_facts through boto. Doesn't not change current behavior. 
This is useful if one uses ec2 to create and instance and ec2.py as the dynamic inventory. 

If one creates a new instance they will not have the ec2_tagname_tagvalue available in the same playbook.
This solves this issue. 

Example: 
```
- local_action:
    module: ec2
    key_name: test key
    instance_type: c3.medium
    image: ami-12345
    wait: yes
    group: new 

- name: get facts
  action: ec2_facts use_boto=yes region=us-west-1
 ```