Continued:

Continued:
- Per definition, filters are classes. So let's add _class into their
  configuration keys to have the later testing suite easily pick them up
  for testing.
- implemented enableSocketNonBlocking()
- imported InvalidServerSocketException
- let's get peerAddress (old: peerName) and peerPort via call-by-reference and
  as all the other socket methods result as returned value
- always initialize variables, before using them ...

Signed-off-by: Roland Häder <roland@mxchange.org>