doctrine/phpcr-odm — pull request #346 by dbu (2013-09-27 14:41:29+00:00)
Title: be more helpful when a user is confused and doing weird things

this cost me quite some time to figure out why i got strange errors about `spl_object_hash` expecting an object. these checks improve the error messages. also adding some more sanity checks on child and children that we only had for references until now.