Require coffee-script >= or ~> 2.2

[johnbintz]

coffee-script 2.1.3 and below use console.log to print out the results of the compilation. When used with Node.js, console.log uses sprintf()-style interpolation to fill in values in error messages, so format character groups (such as "%d") get replaced with NaN when writing out compiled CoffeeScript. coffee-script 2.2.0 does not use console.log so these characters are correctly passed through. Requiring coffee-script 2.2 (and above) will ensure that people using characters that could be trapped by a console.log call will not be.

[johnbintz]

I take this back for now, the 2.2 coffee-script gem doesn't want to use my install of Node.js coffee for some reason.