kqueue: Don't panic on events for unknown fd.

Temporary workaround to be fixed.
Add String method to EventInfo Interface
Merge pull request #46 from ppknap/wip

Add String method to EventInfo Interface
Make the notify cl tool a little bit more verbose
Fix too excessive sed rewrite (use gofmt/eg!)

Took opportunity and renamed FileName -> Path (the returned string is
an absolute and clean path, FileName gives impression of a base name)
Windows - make events printable
Merge pull request #47 from rjeczalik/sed

Fix too excessive sed rewrite (use gofmt/eg!)
Fix for Windows

Weird, I've pushed the change to sed branch before merge and it wasn't
included -.-.
Reconfigure Travis CI to build under Mac OS X