* Add support for threads request

* Address review comments

* Relax threads test condition

* Address review comments

* Clean up unnecessary newline

* Respond to review comment
Co-authored-by: NPolina Sokolova <polinasok@users.noreply.github.com>

* service/dap: Add support for debug and test modes

* Address code review comments

* Remove //dap comment

* OptFlags() => optfalgs()

* If mode => switch mode

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

* Remove hardcoded tests

* Cleanup - consistent naming, simplify some code, remove unused func

* Address review comments

* Add Seq checks back

* Address more review comments

* Remove hardcoded tests

* Cleanup - consistent naming, simplify some code, remove unused func

* Address review comments

* Add Seq checks back

* Address more review comments

* Make more consistent

* More consistency

* Simplify Except* methods with a helper

Mark t.Helper() where appropriate

- Move package doc comments so they are recognized as package doc.
- Use t.Helper when appropriate.

* Initial implementation for 'dlv dap'

* Fix Travis and AppVeyor failures

* Address review comments

* Address review comments

* Regenrate documentation

* Replace dap server printfs with log.Error

* Update 'dap log'

* Fix typos

* Revert logflags changes that got mixed in by accident