Fix invalid integers in spawnpoint command. Fixes BUKKIT-3509

getInteger returns min value on illegal number formats, so we change
behavior to throw an exception when requested.
Updated version to 1.4.7-R1.0 in pom.xml for RB.
Updated version to 1.4.7-R1.1-SNAPSHOT for development towards next release.
Fix ClassCastException for malformed plugin.yml. Fixes BUKKIT-3563

If the plugin.yml gets loaded but wasn't in the form of a map, the
server would crash. This safely checks to see if it can be cast,
throwing invalid description if it cannot.