Inconsistency: content_type and contentType

[360disrupt]

gfs.files.find(newFilter).toArray (err, files)->
 #returns contentType instead of content_type

while gfs.createWriteStream(file) only accepts content_type not contentType and falls back to default value if contentType is submitted.

This requires mapping of param contentType to content_type in e.g. migrations

Expected behaviour: gfs.createWriteStream(file) accepts contentType.