Parses an OpenStreetMap opening_hours tag value and returns it in
a JavaScript object.
The goal is not to parse every possible value but to parse enough to be useful while not destroying existing data. To get an idea of what is supported, please check the [tests](https://github.com/osmlab/jsopeninghours/blob/gh-pages/test/jsopeninghours.js).
If you spot a value that doesn't work like you expect, please file a bug.