experiment 3
cleanup, excise TypeTag
refactor conversions
move defaultTo to end, exceptions in get -> None, test get and getOrElse
add license heading
prototype dsl
functions
more converters
folded dsl work back into configaro.scala
failure to convert to a supported type goes to None, for consistency with behavior of meta-policy type filters
shorten conversion exception names
replace 'enforce' concept with more elegant and flexible 'notify' functions
custom filtering