Updated reflective finding of declared vals in Bundles.

[albert-magyar]

A while ago, I added a check that elaborates the declared fields of a class and examines whether methods share names with fields to determine whether they are val accessors or not (along with other checks, like arity).

This made parameter-less methods returning instances of Data work inside modules, but issue #179 brings up the problem that this won't work in a Bundle. The branch here fixes this issue by performing the new check for val accessors in Bundle instances. In order to reduce the redundant code, I thought it might be a good idea to factor out the generation of a list of methods categorized as val accessors into another object's method.