Accept "*.yml" as input in addition to "*.yaml"

"Be conservative in what you do, be liberal in what you accept from
others"
Merge pull request #166 from interagent/brandur-support-yml

Accept "*.yml" as input in addition to "*.yaml"
Moved code from bin/prmd to lib/prmd/cli.rb

This allows users to execute Prmd using the CLI module instead of the bin
Updated Version module
Break CLI.run into smaller more managable pieces

Actually, quite a bit of work went into this.
In addition to being able to write directly to a file using the --output-file option.
Refactored requires

Why so many File.join/expand_path's?
Moved -o option to individual commands

Had to pull some hacks to get it working correctly
Refactored combine
Simplify verify command
Simplify render and doc commands

Since doc is just a curried render
render will abort if :template key was not given
FEEL THE FURY (Updated README)

Of Badgefury that is
Allow multiple options for http request header via :http_header
Template, load once, use multiple times
Custom response_example
Cache templates
Links can now modify the http_header

For any reason you need to though.
Headers are merged with the default heads.
That means you can't remove a default header.
Fix for backwards compatability with content_type