Allow POST to _log.
Allow POST to _log.

POST /_log {"level":"info|debug|error", "message":"your message here"}

Patch by Robert Newson.

Closes COUCHDB-464

fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb,fkaempfer/couchdb