Improves build process and linting

 This (and I hope the following commits) will be addressing https://github.com/melonjs/melonJS/issues/47 Basically I have done a couple of things. First, I have moved jshint options into a separate `.jshintrc` file. It is a common practice, since a lot of editors look for such file and can lint based on these options.
 Next, I've split the linting process into 2 sub-processes - one ran before concatenating files and the other one after concatenating files. I think this is a good way to force code consistency for style guide.
 So, with this done we can focus on reducing the warnings, but I still need feedback for what you guys think. Maybe I should've used tabs instead spaces, but I will fix it in the next commit?