-> "Pdo mapping"; created ecrt_slave_config_pdo_assign_clear() and
ecrt_slave_config_pdo_mapping_clear().

therefore added EC_REQUEST_INIT and renamed EC_REQUEST_IN_PROGRESS to
EC_REQUEST_BUSY and EC_REQUEST_COMPLETE to EC_REQUEST_SUCCESS.

ec_pdo_t and ec_pdo_entry_t classes, added fmmu_config_t, adjusted
minimal example, etc...

ec_master_calc_addressing(), coupler_index and coupler_subindex variables.
Adapted lsec script and examples.

machines, added datagram injection, two different master thread
functions.

pdos_registered flags and pdo_slaves_offline counter.