Support operating bytes type protobuf field

[samyycX]

As the title said, this PR allow plugins to read/write bytes type protobuf field.

[roflmuffin]

Have you got an example plugin/proto you are using to test that this is working?

[samyycX]

Have you got an example plugin/proto you are using to test that this is working?

Hook Usermessage 208 (CMsgSosStartSoundEvent) and read the packed_params field, it will be triggered when player make sounds

[roflmuffin]

LGTM, I'll test it quickly later today