ec_master_sync_io(); introduced events in the master state machine;
locking of slave scanning and slave configuration through allow_scan
and allow_config flags.

global.

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

ec_pdo_entry_t, respectively.

guessing, ignoring base_sync_count.

pdos_registered flags and pdo_slaves_offline counter.

slave->online to ec_online_state and introduced
ec_slave_set_app_state().

space are now queued and block until completion. Also, appropriate error
codes are returned.