Add tests for connection events

This is groundwork for adding more events in #732.

Sadly I couldn’t put these higher up in the test hierarchy, because the
Grizzly provider doesn’t seem to fire most events.
Add additional handler extension callbacks

Resolves #732.
Add license header to EventCollectingHandler
Merge pull request #747 from barnardb/additional-events

[master] Add handler extension callbacks after DNS resolution and SSL/TLS handshaking, close #732
Made logger static to improve performance. Fixed logger name.
AsyncHttpClientDefaultsTest uses old default value for connectTimeout, close #750
Merge pull request #749 from markus-s24/master

Made logger static to improve performance. Fixed logger name.
Made logger static to improve performance. Fixed logger name, back port #749
Fix handling of multiple double dots above root in parsing of relative URI
Merge pull request #752 from janwe/fix-uri-parser

Fix handling of multiple double dots above root in parsing of relative URI, close #751