Accept accesslevel 'read-write-directmessages'

[boegh]

Currently having the access level as read-write-directmessages results in the error no read-write permission for access token. Strictly speaking this is not right, as the access level read-write-directmessages does give read-write permission, however only x-access-level: read-write is currently accepted.

(one could argue that since there is no need for access to direct messages, one should use that access level, but then the error-message should be changed a bit :)).

[edsu]

This was just fixed.