Add matchLangIP method and primitive

Signed-off-by: Scott Wilson <i@scottwilson.ca>
Add isLocal method to NetAddr

Signed-off-by: Scott Wilson <i@scottwilson.ca>
classlib: Server uses NetAddr:isLocal to detect local

Signed-off-by: Scott Wilson <i@scottwilson.ca>
class lib: NetAddr:matches uses isLocal

Signed-off-by: Scott Wilson <i@scottwilson.ca>
Merge pull request #998 from supercollider/matchLangIP

- Add matchLangIP method and primitive
- Add isLocal method and use it in Server and NetAddr:matches