SSB Log Entry 636

Pigeon Protocol Daily Update

Note to folks just tuning in: I do daily updates related to #pigeon-protocol - a project with similar goals to SSB.

DONE

Did some minor cleanup, removed duplication.
I decided to reorganize headers, but then I realized that headers are order dependent, which I don't like.
Continued the discussion about sigils. Any final comments? Please keep in mind that the message format is intended for use by developers rather than end users.

I think this is what log entries will look like now:

``` author FEED.BVQCXBFKH2PMYJ3W4CRD8JEA82JB3PC9T0RVCZAAD0S2ENZ6WANG.ed25519 prev TEXT.ZG8XJM3BDQBVSPNCJFQ7JZ2X0229STJH32MH80793SHX2YKAAXDG.sha256 lipmmaa TEXT.3NPHB4BHTJ9RXZTNGY5YY84DNHQQY3TY2ZD2QMAQYW8NMBA1W3HG.sha256 depth 2 kind blob.add

author:FEED.BVQCXBFKH2PMYJ3W4CRD8JEA82JB3PC9T0RVCZAAD0S2ENZ6WANG.ed25519 file_checksum:FILE.YPF11E5N9JFVB6KB1N1WDVVT9DXMCHE0XJWBZHT2CQ29S5SEPCSG.sha256 description:"A really cool mix tape." whatever:"foo, bar, baz, blah…"

signature SMP6M…redacted_for_legibility…EXW2G.sig.ed25519 ```

TODO

Allow headers to be placed in any order.
Change @, %, & to FEED., TEXT., FILE., respectively.