Ignore body of response completely

Hopefully a fix for varspool/Wrench#21
Key is already base64 encoded
Updated API documentation
Whitespace changes
Make case-insensitive header comparison

Fixes varspool/Wrench#28
Process and return the protocol header
Allow multiple request headers with the same name

For example, Sec-WebSocket-Extensions
Test request parsing

Including verification of varspool/Wrench#28 and multiple extension
headers
Updated version