Cleanup improvements and wdm fixes

Improvements related to contributing and debugging and some WDM fixes/workarounds:

#### major
* refactor acceptance tests for readability
* fix failing specs (WDM)
* cleanup Gemfile + add notes

#### minor
* refactor out adapter async startup
* show crashes in record
* show log level on debug startup (Listener)
* avoid crashing when terminated
*  add debugging (Directory)
* add extra debugging (Change)
*  add extra wdm debugging
* add temporary debug logging (for wdm)
* fix os detection in specs