Change FilterFactory code to pass in the actual Description

I still need to write more tests, but I wanted to send this out for an early look.
I mean rather than:

if (arg.startsWith("--filter=") || arg.equals("--filter")) {
  if (arg.equals("--filter") { A }
  else { B }

Just do

if (arg.equals("--filter") { 
  A 
} else if arg.startsWith("--filter=") { 
  B 
}