Initial work-in-progress implementation for resource interfaces.

Provides resource/object oriented interfaces for AWS resources.
built using service clients.  Examples:

    # nested resources and actions
    s3 = Aws::Resources::S3.new
    s3.bucket('aws-sdk').object('key').delete

    # collections
    ec2 = Aws::Resources::EC2.new
    ec2.instances.each do |i|
      puts "#{i}.id => #{i.status}"
    end

    # batch operations
    s3.bucket('aws-sdk').objects(prefix:'/temporary/').delete

Resource classes are defined from a per-service definition
in a manor similar how the API clients are defined.

A number of the unit tests are currently failing, and there
are a few known issues/limitations including:

* Resource definitions exist only for ~6 services.  More
  definitions needed.
* No support for passing resources to other resource actions.
* No support for default resource operation params, only static
  params that can not be overridden.
* Limited API documentation for resource operations. The documentation
  plugin work is on-going.
* No tests for batch operations.