Missing entries in "Allowed PDUs per State" table

[martinkrammer]

The "STC_do_step" PDU can be received in SYNCHRONIZING and SYNCHONIZED, not only in RUNNING.
A "1" should be added to the corresponding columns of line "STC_do_step".

Note: Transferred from https://github.com/modelica/dcp-design/issues/209

[clemensschiffer]

Additionally, in state SYNCHONIZED receiving of STC_run is allowed, an 'R' should be put in the table for this combination.