Fixed some memory cleanup and destruction issues with ContextObj, ECData, CDList...

Fixed some memory cleanup and destruction issues with ContextObj, ECData, CDList, and CDMap. Added the d_underTheShotgun field to NodeManager to keep track of which NodeValue is currently being deleted. If a Node or TNode has this node value, it can always be deleted.  This avoids the need for introducing SoftNodes.  Currently passes Debug and Production make check