Fix undefined local variable or method `klass'

klass and id were not defined when deserializing ruby objects, causing an undefined error when trying to raise a DeserializationError. This should be fixed now.
[ADD] use_active_record_lookup config
Merge branch 'undefined_klass' of git@github.com:ciihla/delayed_job.git

Conflicts:
	lib/delayed/psych_ext.rb