-- NEW:  Add _EXPMAC keyword, to force macros to expand in both the taken and
    not-taken branches of an IF.  This is needed for IF-statements inside a 
    RPT block, whose taken/not-taken behavior varies across loop iterations.

 -- NEW:  Increase resolution of release_date to incloude hours, minutes,
    seconds, and timezone.

 -- NEW:  Add build_date and version CFGVARs.
     -- build_date takes the same format as release_date.
     -- version is an arbitrary format string.
     -- Both tags can appear an arbitrary number of times.

 -- NEW:  Add %z specifier to TODAY_xxx.  
     -- Reports timezone as +HHMM in TODAY_STR_xxx.
     -- Reports timezone as minutes relative to UTC in TODAY_VAL_xxx.

 -- NEW: Add _ROTL16, _ROTL32, _ROTR16, _ROTR32 operators.
     -- Same precedence as SHL, SHR, SHRU.

 -- Internal:  Increase IF-ELSE-ENDI stack depth from 32 to 256.

 -- Internal:  Additional infrastructure for normalizing metadata between
    different object file types.

 -- BUGFIX:  Add missing __FEATURE.TODAY for the TODAY_xxx feature.
    This was supposed to be in the last release, but a fatfingered edit
    fail deleted it.

 -- BUGFIX:  Fix some nested RPT cases.
     -- Multiple RPTs inside a nested RPT now work.
     -- RPT guarded by an IF also now works.

 -- BUGFIX:  Fix some metadata tag behavior when loading ROMs w/ tags.

 -- Misc:  Start marking stuff 2018.

 -- Misc:  Update documentation for new features.