Using a stop channel to signal clean shutdown to the server's
goroutines. Also updates the tests to trigger disconnectChan.
This helps avoid spurious error logs when the client disconnects, when
Ctrl+C is pressed, etc.
* Panic guard for DAP request handling
* Use GetSeq
* Re-vendor new version of go-dap
* Remove comment
* Update error message
* Reuse er.Message in Format