and remove old dependency field (never used, was always NULL,
broken since 3.2.x)
I'll add some constraints later on things like names and versions.
IOTW: more changes to follow, don't mass update your own mods yet.
So rename src/modules/m_*.c to src/modules/*.c and update makefiles
and modules.default.conf. Also remove m_ at various places in the
source files, but not the CMD_FUNC(), just the module name.