Improve error handling

Fix assorted bugs and return packet kind (#8)

* add connection state

* improve error handling

* fix segmentation fault while attempting to close closed socket

* implement auto-close

* remove gcsafe requirement from onAutoClose callback

* remove auto-close

* return packet kind

* remove auto-close unit test

* make interface more consistent

* omit double copy

SSL support

0.2

Chronos SSL support (#6)