emit errors instead of calling process.exit()

Improvement to #520 error handling
emit errors instead of calling process.exit()

Improvement to #520 error handling
Merge branch 'emit-error' of github.com:Resseguie/johnny-five into emit-error

Conflicts:
	lib/board.js
Merge pull request #541 from Resseguie/emit-error

emit errors instead of calling process.exit()