Description:
------------
Hello I got the following exception launched on method ($HttpRequest)->send():
HttpInvalidParamException .
But this is not listed on current documentation.

Also the exception parent class HttpException is missing on docs.
Could you add the exception related classes to the Http package documentation.

That would be nice for first users of this package.



Test script:
---------------
# point to some url that will not response #
$req = new HttpRequest(
        "http://anyurl-that-will-timeout"
       ,HttpRequest::METH_GET
);

$req->send();



Expected result:
----------------
An exception from the listed ones on documentation.

Actual result:
--------------
Fatal error: Uncaught exception 'HttpInvalidParamException' with message 'Empty or too short HTTP message: '''