Handle commandBlockOutput GameRule for Command Minecarts.

Fixes BUKKIT-5207
Updated version to 1.7.2-R0.2 in pom.xml for Beta.
Updated version to 1.7.2-R0.3-SNAPSHOT for development towards next release.
Merge commit '1227b64c8af479322a440de24431c7dc057c9655' into master-spigot

Conflicts:
	pom.xml
apply latest spigot-changes