Port Optimize NextTickList processing patch for 1.7.x

This is a port of the previously removed diff from 1.6.x : some of the changes in 1.7.x broken the previous patch.  This update should address those issues.

A test build of the latest Spigot code, with this fix, can be found at http://mikeprimm.com/spigot-1.7.2-R0.3-SNAPSHOT.jar