extracted Errors
skip relative schema imports for now

if someone finds a specification for dealing with those,
please let me know.
BindingOperation#input now returns header and body
updated the changelog [ci skip]
removed the dependency on HTTPI /cc #27

Since Wasabi only does GET requests, it only needs a very simple
interface for sending HTTP requests which works great with testing
and allows you to use any HTTP client via a very simple adapter.

see spec/support/http_mock.rb for an example.
updated the readme and changelog [ci skip]
fixed the http client example [ci skip]
simplified the HTTPClient example [ci skip]
added Element#singular?

this allows us to properly expect and return arrays.
marked slow spec on rubinius as pending for now
fixed grammar [ci skip]
prevent nasty recursive element type definitions
introduced proper logging
formatted log output.
raise an error if we're missing an http object
added specs from savon
removed duplicate spec
added three more integration specs