Allow http token authorization to set token_authentication_key in place of passing it in via params

It will not override existing token_authentication_key params if they are present.
fix hanging line on method call
adding http token auth options to env[devise.token_options]
renaming devise option "allow_authorization_to_set_auth_token" to "allow_token_authenticatable_via_headers"
removing params hash merging of token and mimicking http basic auth flow
update devise config template with new allow_token_authenticatable_via_headers options
Merge pull request #2271 from robhurring/master

Allowing http token auth to set the token_authentication_key if missing from params