Improve javadoc in 26 files.

Addresses:
BUKKIT-1643, BUKKIT-1868, BUKKIT-1846, BUKKIT-2632, BUKKIT-3196,
BUKKIT-3187, BUKKIT-3198, BUKKIT-3200, BUKKIT-3201 and BUKKIT-3417.
Don't try listing something that may not exist. Fixes BUKKIT-3471

The player name may not be provided, in which case the command will
fail hard.
Only use TravelAgent if supplied; Addresses BUKKIT-3466

If there is no TravelAgent assigned, it can not be used.
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.
Pulling all pending Bukkit-JavaDoc changes
Add PlayerItemConsumeEvent. Adds BUKKIT-2349