remove support for versions prior to turn 572 (INTPAK_VERSION).
reading anything prior stopped working some time ago, let's not kid ourselves.
nobody needs to read those datafiles, they are more than 7 years old.
less code is better.
if access to these files is needed, check out an old version from source control.
remove even more obsolete datafile version support.
remove some inactive #define macros and the code that goes with them.
mostly rules that were experimental, but have made it into common use (not worth the effort of making them configurable).
Merge pull request #67 from badgerman/version-cleanup

eliminating support for old datafile versions, prior to binary formats