#31 Content type and length switching rules

Provides a patch to work around a bug in the built in PHP server.
the spacing seems to be a tab to me. Yes I am looking at https://github.com/jakeasmith/Aura.Web/blob/6f8dca3beb82f5face930f07d9361ff69db90b7b/src/Request/Content.php#L104-L111 .