Added a test for extra CRLF lines in keep-alive connections
Support for non-RFC compliant header prefixes

When using keep-alive connections, some HTTP implementations insert unexpected and extra CRLF tokens between each connection, which can result in the next request being prefixed with a CRLF.

Some other client/server implementations are tollerant of this, and for example this bug doesn't show up when using the Go net/http library.
Added a regression test for keep-alive chunked POST
Fixed a bug with keep-alive chunked requests

If you make a POST request with 'Connection: Keep-Alive' and use chunked body encoding, tornado will not interpret that as a connection that can be kept alive, and will close the connection.
Fix a potential leak of an unclosed AsyncHTTPClient.
Merge pull request #1124 from duedil-ltd/non-rfc-crlf

Support for non-RFC compliant header prefixes
Cite RFC 2730 when stripping extraneous line breaks.
Merge pull request #1125 from duedil-ltd/chunked-encoding-keep-alive

Fixed a bug with keep-alive chunked requests