Added a note about 'no space left on device' error, issue #68 involving OS configuration
Update readme to specify BSD / OSX limits.
Add the test from Issue #71 and fix it.

The issue was that files watched internally were not being removed
when the parent directory's watch was removed.
Fixes issue #70

Not exactly the best fix, but it'll do.
Merge remote-tracking branch 'origin/master' into pipeline

Tracks external watches

Conflicts:
	fsnotify_bsd.go