Consider arguments to team leave properly. Fixes BUKKIT-3994

Two checks to argument length were changed to properly consider if the
sender is a player instead of an off-by-one logical error.
Spigot POM Changes.
Measure the duration of the entire timings run.
Improved Timings System

Enables "Timings on Demand" so you can enable/disable timings without server restart.
Tracks timings on sync events a plugin registers (Single and Repeating)
Tracks how many ticks a timed area has caused the server to lose due to taking too long.
Enables automatically pasting to paste.ubuntu.com so you can quickly review the results on aikar.co/timings.php
Add nag for bad plugins.
PlayerItemDamageEvent