[c-lightning] Feature freeze in preparation for 0.6?

[ZmnSCPxj]

Good mornig Rusty,

Starting a feature freeze is fine, it has been more than a year since previous release.

It would be nice to have Tor support, but the existing Tor support code predates #1322 and it will require some effort to adapt to the changes, so it is OK with me not to schedule for 0.6 (but hopefully in a closely-succeeding release).

Now specifically:

> 1.  The proposed gossip spec enhancements.
>     
>     I've implemented it, just got to test it. It's important for other
>     
>     peers as it greatly reduces their bandwidth requirements, and I'd
>     
>     prefer not to have them avoid our peers because we spam them.
>     

Seems good, have not read the new specs in detail however.

> 2.  Adding an SHA256 tag to the gossip store.
>     
>     The gossip store is append-only, and not synced: a checksum allows us
>     
>     to ensure it has been saved correctly. This change will require
>     
>     the store to be re-synced, so it's best to do this now before the
>     
>     network grows too large.

SHA256 seems overkill, as cdecker pointed out in a comment in the github issue.  I mostly agree with using a simple checksum (CRC?).

The version field in `gossip_store` helps, but it would require a conversion pass at startup.  Or we could just truncate a version-0 `gossip_store`.

Regards,
ZmnSCPxj