Moved ValidationTransformTests.scala to the correct package
Hackish POC pending discussion on issue #7
Still hackish, but starting to take shape
Switched failures to a violation-set representation (previously was an ordered sequence, which assumes some evaluation order and doesn't deduplicate e.g. null issues).
Proof-of-concept solution to issue #7 (note massive behind-the-scenes API chagnes on the branch).
[#7] Added a type constraint to BaseValidator so it only applies to reference types + cleared up some leftover code
[#7] Introduced NullSafeValidator (adds a null safety layer over BaseValidator) + added a bunch of reference type constraints