cmd/cored: fix auth on unconfigured core
cmd/cored: fix auth on unconfigured core

Populate the core.Handler with an accesstoken.CredentialStore when
launching an unconfigured Core. Unconfigured routes still need access
token authentication.

Bug was introduced in #48.

Closes #56

chain/chain,chain/chain,chain/chain,chain/chain,chain/chain,chain/chain