Rename CMD GW script name

`OAC_CommandGateway.lua` is too long and cannot be processed by
FSUIPC. It's renamed to `OAC_CMDGW.lua`.
Fix invalid address parsing bug in oacsp.h

The addresses for FSUIPC offsets were wrongly parsed when received
in events. This fix uses `strtol()` to parse the hex number rightly.