document "dilation-abilities" key in the versions message

[vu3rdd]

Python client sends a key called dilation-abilities in the versions message jSON payload. This seem undocumented in the dilation specification.

{'can-dilate': ['1'], 'dilation-abilities': [{'type': 'direct-tcp-v1'}, {'type': 'relay-v1'}], 'app_versions': {}}

[vu3rdd]

The versions spec documentation refers to this as abilities? Or am I confusing it?

There is also some discrepancy with that document referring to abilities like dilation-v1, which the dilation spec doesn't define.

[meejah]

As currently written, the code sends versions as strings -- I think we should send integers (well "numbers" in JSON speak) to be more clear. The "please" message also doesn't send the "use-version" that it is supposed to -- I think this is a thing we do want to send. Perhaps it's missing because there's only a single version currently, but being consistent here now I think has lots of benefit.

[meejah]

Actually, I did find a reason that strings are used for versions: then implementations can use this for "non-official" or experimental versions easily without trying to figure out "a number" to give it.

The preference order comes from the order in the list.