Feature value parsing and camel case

This pull request adds non-breaking support for camelCase. Camel case will only be supported when a `__` is detected in the key. To force top level keys to be camel case, you can add a trailing or leading `__` to the key.

This also adds support for parsing booleans, numbers, etc (anything JSON.parse can handle).

Finally, per @ifandelse, this is a major version bump (to 1.0.0) to mark the breaking nature of the parsing change.