Add `filterNot`
It's common enough to have it as convenience method I think.
It's also one of the typical scala collections methods, so having
it around is nice for people coming Scala expecting it to be there
"just like in scala".
use _ syntax for fn
style fix
added `filterNot` to `TypedPipe`
incl. test for both filters
[formatting] empty line between classes
Merge pull request #729 from ktoso/filterNot

Add `filterNot` to RichPipe