use tape instead of mocha

https://github.com/substack/tape
report code coverage to Coveralls.io

https://coveralls.io/r/shinnn/can-play-type-to-number
test on AppVeyor

https://ci.appveyor.com/project/ShinnosukeWatanabe/can-play-type-to-numb
er
introduce gulp-jscs
add .gitattributes
update readme