Add HTTP::ResponseBody#empty?
Normalized reponse headers

Resolves #74
Add response header tests
Fix header merge implementation
Rename request/response classes to better match Reel

This factors the classes used by requests and responses within the namespace of
the Request and Response classes. The names are changed to better match Reel:

* HTTP::RequestStream  => HTTP::Request::Writer
* HTTP::ResponseParser => HTTP::Response::Parser
* HTTP::ResponseBody   => HTTP::Response::Body
Merge pull request #75 from tarcieri/name-cleanups

Rename request/response classes to better match Reel
Update Travis settings for Rubinius.
Fix typo in Response#charset
Consolidate Errors
Remove redundant private statement
Merge pull request #79 from brixen/master

Update Travis settings for Rubinius.
Fix mixed case headers merge specs
Merge pull request #78 from tarcieri/feature/errors-consolidation

Consolidate errors unders HTTP namespace
Allow using URI instances for request building.
Indent properly
Check that uri is a URI or string before converting.
Merge pull request #81 from mje113/master

Allow using URI instances for request building.
Unify work with headers across request/response
Merge pull request #80 from tarcieri/improvement/headers-cleanup

Unify work with headers across request/response
Remove pry-rescue from Gemfile