Revert workaround introduced in 6444ec06052bad0efd2f85e75b9c966bc38bdd83
Fix ValueNode_Random::clone. Still crashes later inside of Layer::connect_dynamic_param().
Change ValueNode::clone() return type - use ValueNode::Handle instead of pointer
Fix another crash related with pointers usage. Now #482 should be fixed.

See http://www.synfig.org/issues/thebuggenie/synfig/issues/482
Merge pull request #64 from morevnaproject/random-dup-fix

Fix for #482
Update valuenode_step.cpp

Fix spelling of word