Ref: ad39d6b2

Ensure that all evals include file and line number to identify their
source.

Two of the evals reported by this cop were unneccesary and replaced with
non-eval alternatives: xml is set as a local variable in
Template::Handlers::Builder#call, and instance_eval isn't needed to get
the current binding.

There are additionally 27 offenses in test directories, but since it
seems less important to fix those they are currently ignored.