Added a check for global.Buffer before .isBuffer

Need this check for the future where we remove the browserify insertion
of Buffer. It is also cleaner to check, I believe.
Merge pull request #4 from kevin-roark/fix/global-buffer-check

Added a check for global.Buffer before .isBuffer
Merge branch 'upstream' into add/better-binary-events

Conflicts:
	index.js

Removed the complex binary encode stuff from upstream.