Syntax error checking on build.

[airportyh]

This implements syntax error checking on build: componentjs/component#478 - based on tag 0.10.0.

Here are benchmarks which show that this change has negligible performance impact:

https://gist.github.com/airportyh/9014213

[jonathanong]

ohh got it. only things i can think of off the bat is 1) style and 2) make sure you're reading a .js file for robustness since some people like to put their coffee in scripts (though i'm not exactly sure how it'll work right now if someone has coffee files in scripts without using a coffee plugin. just want to make sure it doesn't crash).

[airportyh]

@jonathanong please check new commits to address #1 and #2. I had no idea component supports CoffeeScript.