Removed some left-over models from the apis/source directory.
Added support for a customized EC2 protocol.

The EC2 protocol is based on query, but has specialized
rules for serialization.  The API model has undergone a few
updates to enable to it be full normalized and still describe
the API correctly.

This currently lacks unit tests and not suitable for shipping.
Moved paging logic into its own module, Aws::Paging.

Additionaly extracted a few more useful classes including
Paging::NullPager, Paging::NullProvider.
Removed an unsed function in the api documentation plugin.
The endpoint provider now returns nil when an endpoint can not be resolved.
Added EndpointProvider#prepend_all

Prepends an endpoint rule for every service.
Removed the bundle ca file.

Users will need to ensure their system is correctly configured with the
proper open ssl ca bundle for HTTPS peer verification to work.
Removed EC2 specific tests from query protocol tests.
Added input & output protocol tests for  protocol.