Update grunt-contrib-coffee to 0.9.0: Internally, CoffeeScript is updated to 1.7.0
Transfer generation of test.js to grunt from testem
Implement `promisify()`
Merge branch 'master' into gh-pages

Conflicts:
	Gruntfile.coffee
	package.json
	src/zazen.coffee
Merge branch 'master' into gh-pages

Conflicts:
	Gruntfile.coffee
	package.json
	src/zazen.coffee