Consistent method names (camel/snake case)

[nonplus]

Most of the APIs in the library consistently follow JavaScript naming conventions and uses camel case (parameter and method names).

However, several of the classes have a mixture of snake-case and camel-case method names. For example, DecisionsResponse has an add_marker() method and an addDecision() method. Similarly, EventList() has a has_timer_event() method and an eventById() method.

It would be nice if the public API of the library consistently used camel case for method names. For backwards compatibility, the existing snake-case function names should be kept as (deprecated) aliases.