Update README badges and re-add Travis
Make ec2 endpoint configurable.

To support custom implementations of EC2 API.
Document endpoint attribute [ci skip]
Try to use dns_name before public and private ip address
Add ebs_optimized attribute
Spelling (optimize -> optimized)
s/groups/security_group_ids/g and add security groups to the configuration example
Use value of region when determining default endpoint value.

References #27
Revert README sections.
Update YAML examples to use modern syntax in README.
Remove require_chef_omnibus & sudo documentation from README.

These are now Provisioner concerns.
Update project links in README.
endpoint should have a trailing slash per https://github.com/fog/fog/issues/583
Merge pull request #31 from spheromak/master

endpoint should have a trailing slash