latch & latch-to-lock

RMLVO enumeration?
  - needs XML :(

larger group numbers

merge ExprResolveKeySym and LookupKeysym?

~/.xkb/rules.local + ~/.xkb/keymap.local
  - /etc/default/keyboard?
  - accept NULL for RMLVO compilation

remove core mods
 - xk-c patches

xkeyboard-config:
 - flatten compat and types
 - kill modMapMods, make everything explicit
