If one wants to temporarily disable the key cache (for example because
it interferes with a macro), `disable_action_cache` must be set to
`true`. `process_action_nocache` is a simple wrapper doing just that for
a single call.
- new macro_mods bit field for mods applied by macros
- weak_mods now only used for ACT_{L,R}MODS (i.e. LSFT, RSFT, LCTL etc.)
- clear the _weak_ mods on every key *pressed* such that LSFT etc.
can no more interfere with the next key
