#11 Support vendor-specific SMPP commands

[Oran Kelly]

(From the forums:)

"There are reserved for SMSC vendor command ids mentioned in SMPP spec.
How can I handle these commands?
The only way I see is create new Packet class extending SMPPRequest and
this is ok. Bad thing that I must edit original PacketFactory and SMPPPacket to include
handling for new commamd ID. Is there any other way to extend command set without hacking
original sources?"

The API should be able to handle custom, vendor-specific commands without hacking the API source.