Allow us to check for a value in a struct
Revamp version checking, support revision 16 files

We're once again going to treat the revision field
as a float, and do compare on a string
representation of it for the purposes of figuring
out file revision.

Kids! Never make your revision number a float.
No longer floatify command-line revision forcings
Add support for WTF fields in r16 headers

They seem to have patient data; let's allow
anonymization of them.

Also, now we check to see if a field appears in
a header before we try to anonymize it, so we
can get reasonable debugging messages.
Bump version, README