Connection: close header support

Respond to "Connection: close" header (#157)

Presence of request or response with "Connection: close" header will make that the final stream before the connection shuts down.

fix shared lib build, code clean up

Fixed missing exports of h1 connection. (#156)

* Fixed missing exports of h1 connection.

Fixed content-length=0 being treated as illegal for bodyless messages.

v0.4.8

Fixed error condition for when content-length=0 is set on a response …

Integration tests support aws-crt-python

v0.4.7

changes to support testing aws-crt-python/elasticurl.py (#148)

Moved connection manager tests to net_test

v0.4.6

Moved connection manager tests to net tests, even though some don't n…

fixed mixed static/shared builds.

v0.4.5

Fixed dll/.a hell in the same build closure. (#146)

LTO support for Clang/GCC

v0.4.4

aws_http_header_type -> aws_http_header_block (#143)

Connection manager shutdown callback + edge cases

Connection manager shutdown callback support (#136)

* Connection manager shutdown callback support

* Dummy change to trigger CI

Library init/cleanup

v0.4.2

Const options (#131)

Manager fixes + proxy configuration additions

Manager proxy (#127)

* connection manager proxy configuration
* websocket proxy configuration