Removed the overridden Property#kind_of? method
Removed the overridden Property#kind_of? method

* All specs pass without this method explicitly defined, so it is safe
  to remove this. Besides, it's rare to override #kind_of? except in cases
  where you are proxying to another object, which is not the case here.

tillsc/dm-core,alloy/dm-core,ar-dm/ardm-core,tpitale/dm-core,engineyard/dm-core,datamapper/dm-core