Avoid ClassCastException when mixing normal and snapshot instances.
Avoid ClassCastException when mixing normal and snapshot instances.

tempbottle/jsimpledb,gmsconstantino/jsimpledb,mmayorivera/jsimpledb,archiecobbs/jsimpledb,archiecobbs/jsimpledb,permazen/permazen,gmsconstantino/jsimpledb,tempbottle/jsimpledb,permazen/permazen,mmayorivera/jsimpledb,tempbottle/jsimpledb,gmsconstantino/jsimpledb,archiecobbs/jsimpledb,mmayorivera/jsimpledb,permazen/permazen