Create config option for specifying full default cidv1 parameters

[kyledrake]

Create a config file option to set cidv1 and encoding for output of API / commands.

https://github.com/ipfs/ipfs/issues/337

@kevina

[kevina]

I believe we should have the following options:

• Default.CidVersion -- the default CID version of newly created hashes
• Default.CidBase -- the default base to display CIDv1 hashes, CIDv0 hashes are unaffected
• Default.CidHash -- the default hash to use for newly created hashes if CidVersion > 1

Note that defining Default.CidVersion > 1 also implies the use of raw leaves when applicable.

These are also only defaults. Command line flags will override this so will parent CIDs within the Files API.

The question is should we separate things like Server defaults, Client defaults, and Gateway defaults or is this not worth the trouble?

[kevina]

@whyrusleeping @Stebalien does this sound reasonable to you?

[RubenKelevra]

I would love to have the ability to lock down the CID-Version to v1 in 0.5.0, since currently I end up with a some CIDs in v0 and some in v1.

This is quite hard to debug, since there's a breaking change for 0.5.0 which makes the CIDv1 in the DHT incompatible with 0.4.x.

So some requests might fail, while others might work. And if there's a request for a v0 before, you might up ending getting v1 CIDs as well, since bitswap asks directly thru the open connections.

[ec1oud]

Why is this not done? Seems like not very much work?