PeerId from HTTP API

v0.22.0

Adds new gateway' status fn retrieving a PeerId from HTTP /node/statu…

PeerId && Token

Includes PeerID in Leth token generation.

Bumps the version to 0.20.0.

Does not include the fixes to hardcoded JS needed to make the
example work on Leth.

v0.20.0

Fixes broken migration.

Shop.create

Merge pull request #21 from lightstreams-network/shop_create

Renames shop.initialize to shop.create