restrict types on files

[jonathanong]

do you guys want to force types on files? here are my thoughts:

• scripts must be .js files
• styles must be .css files
• json must be .json files

thus, i want https://github.com/component/spec/issues/25 for any source code that compiles to above.

[jonathanong]

just noticed that the current specs say "scripts must be regular Javascript`.

how about this: public components must only have JS files as scripts. private components should.?