PSR-2 Coding Style

I've made this repo confirm to these standards where possible. The same issues apply as in iron-io/iron_core_php#7.

Also note the session_xxx functions aren't psr-2 compliant because they aren't camelCase. I also added public visibility to them since psr-2 requires that (they had no visibility, so php would default them to public anyway).

One other note, `/* PRIVATE FUNCTIONS */` tag actually has protected functions after it. I haven't changed any of that.