Xenial is now available with Travis CI
https://blog.travis-ci.com/2018-11-08-xenial-release

nghttpx allows a pattern with trailing slash to match a request path
without it.  Previously, under certain pattern registration, this does
not work.

h2load: Handle HTTP/1 non-final response

cmake: Fix libevent version detection

Use __has_declspec_attribute for shared builds