Fixes, fail testing:

Core:

* Test buffer_cat iterator move members

HTTP:

* Fixed yield / resume in writer
* Fixed message serialization with chunked encoding

* Test yield / resume in writer
* Test all conditional branches during message serialization
* Test chunked encoding
* Increase coverage on parse_error
* Add parse_error::general

WebSocket:

* Add error::general
* Increase coverage in error

scripts/run-with-gdb.sh

@@ -3,6 +3,7 @@ set -e
 gdb --silent \
     --batch \
     --return-child-result \
+    -ex="set print thread-events off" \
     -ex=run \
     -ex="thread apply all bt full" \
     --args $@