Actually fix the bug, which was a doozy:  OrphanBuilder::tag was sometimes initialized using WirePointer::setKindAndTarget(), but since the tag didn't live inside the target segment, this used illegal pointer arithmetic.  The target is never read from an orphan tag anyway, so I thought it would be no big deal.  But it turns out Clang actually optimizes under the assumption that pointer arithmetic returns a whole value.  As a result, on 32-bit system where 64-bit values are only 32-bit aligned, the tag and target might not have been a whole number of words apart, and the extra bit actually found its way into the 'kind' bits, causing e.g. a struct pointer to become an invalid far pointer.  Crash.  The fix required refactoring to ensure that setKindAndOffset() is never used for orphan tags.

Require a colon before 'group' or 'union' except for unnamed unions as well as the legacy case of a named union with an ordinal (where the colon is optional).

Generate usable code for groups, although making schemas work is still an open problem.  I think I'm going to do the schema rewrite now.

Unnamed unions WIP.  About to change MemberInfo format, which will require re-bootstrapping the code generator.

Switch to the new compiler.  All tests pass\!  Need to submit bootstrap copies of the generated code used by the compiler itself.  These bootstrap copies are still built by the old compiler at the moment.

When an under-sized struct is found while traversing a builder, upgrade it to the expected size.  This is needed to allow easy copying from readers to builders.  Next, this will need to be implemented for lists as well.

Restore ability to upgrade from List(Bool) to List(T) where T is a struct whose @0 field is of type Bool.  I previously disallowed this to reduce complexity, but it turned out to actually increase complexity.

Delete Code Friday:  Inline structs/lists/data are too complicated for not enough benefit.  There goes a week of my life that I'll never get back.

Implement 'Object' field type, which can be any pointer type.  The caller specifies the type when calling the accessors.

Improve unions.  Members of a union are now scoped within the union, although they share ordinal space with the parent struct.