[BUG #7182] implemented '@lint ignoreJsdocKey()'

- logging of jsdoc errors is now done in jshint.py
- so that it is possible to check e.g. unknown @hints against preceding
  @lint ignoreJsdocKey() entries up the hints tree
- Comment.py could be freed again from all console logging (!?)
[BUG #7182] applied '@lint ignoreJsdocKey' to Sinon.js

- and re-enabled lint/warn-unknown-jsdoc-keys for the framework 'api' job