adding more visit util functions and checked list binder
more code slimming to use functions in mingle/bind
adding declared type name
adding qname
adding tests for atomic types
making all AtomicTypeReference instantiations go through constructor func
making all RangeRestriction instances go through constructor func
adding tests (but not impl) for range restriction failure checks
first cut of pushing restriction and atomic type creation logic into core package
updating compiler to delegate restriction constructing logic to mingle/core
removing NewRangeRestriction (all code users RangeRestrictionBuilder; adding restriction error tests for io
adding restriction error tests to builtin bind tests
checkpointing first atomic type roundtrips
adding atomic restriction error tests
making Namespace field explicit
adding a todo (unions)
adding type reference bindings
fixing error in mingle/bind test
adding some first material for types binding tests
adding UnionTypeDefinition and CreateUnionTypeDefinition() in advance of some related refactoring