Killing the node process without killing fkill #19

Currently, fkill does a simple pid filter using process.pid to ignore a request to kill itself. On Windows, fkill would also filter out its pid when killing all processes with the name node. Unfortunately, this meant Windows' taskkill always felt it succeeded, even when killing zero processes as a result.

PR #17 removed this feature. It makes fkill's behavior consistent, and also allows for tests to fail when fkill doesn't find an expected target on Windows (see #16).

That's the context. We don't want to kill ourselves when asked to kill node. That's what this issue is about.