fhiclcpp to fhiclcppsimple + some new features

[jedori0228]

• Changing namespace from fhicl to fhiclsimple
• 0d722b2:
  • make_ParameterSet_from_string is added; This is used when converting fhicl to fhiclsimple:

fhiclsimple::ParameterSet nusyst::FhiclToFhiclSimple(const fhicl::ParameterSet& f) {
  return fhiclsimple::make_ParameterSet_from_string( f.to_indented_string() );
}

• 51e4763:
  • I found when fhiclsimple::ParameterSet::to_indented_string is used, string Atoms are converted without quotation marks. e.g., When a ParameterSet with prettyName: "AhtBY" is converted into string, it becomes prettyName: AhtBY