Update message processing to remove obsolete messages.
The following messages are not generated by Version 6.1 components:
BIP2825 BIP5179 BIP5182 BIP5196 BIP5197 BIP5198 BIP5219 BIP5220 BIP5276 BIP5422 BIP5423 BIP5425 BIP5438 BIP5439 BIP5440 BIP5441 BIP5442 BIP5443 BIP5444 BIP5508 BIP5509 BIP5510 BIP5511 BIP5512 BIP5513 BIP5514 BIP5515