When some channels are filtered, some misalignement of channel ids could happen.
This patch keeps track of the back and front channel ids to correctly identify a
channel and send packets with the correct channel id.
* Fixed format strings to match arguments
Reviewed and replaced all %d specifiers to match proper type
* Added proxy dynamic channel command type to log messages.
This big patch fixes fragmentation handling in the dynamic channel. We used to
have a single state to handle fragmentation at the main dynamic channel level, but
in fact packets can be fragmented per sub channel. So we have to maintain a fragmentation
state per sub channel, this involve treating dynamic and static channels differentely
(so the size of the patch that has to implement state tracking per dynamic channels).
The rework introduce a stateful dynamic channel treatment, so that we can take early decisions
for data packet (dropping all the current packet or pass it), but also reassemble important
packets like channel creation.
