Cleanup JS style guide.

* Added `.gitignore`
* Pulled some common elements out of the JS guide into the basic guidelines.
* Added clarification about indenting and alignment.
* Cleaned up JS styles guide to follow the PHP style more closely.
* Removed coding guides from JS (these need more thought, some recommendations where wrong because I suspect they were out of date, and they should probably be moved to an appendix anyway).
* Forced all code blocks, even one-liners to be wrapped in curly braces (too many a bug I've seen happen when we don't do this consistently).

Note, I'm propose that the `else` keyword start on its own line rather than used inline. I think this makes for a better read but it's not a hill I'm prepared to die on.