* Added a stub, dummy udi_mei_init_t for udi_mgmt to the IBM-PC meta init list.
  ^ This will serve as the returned pointer when a call for findMetaInit() is
    made with "udi_mgmt" as the argument.
* DriverInstance metadata now has a list of udi_mei_init_t descriptors which all
  point to meta_inits for the metas that the driver needs.
* There is now a semi-global, per-driver-instance list of region-local metadata
  which allows calls such as udi_channel_spawn() to get their calling region's
  region-local metadata cache.
* Implemented libzudi's udi_channel_spawn().