Changes

SPIGOT-522: Remove the global api cache option

This was useful when plugins first started upgrading to uuid because each
plugin would implement their own way for grabbing uuid's from mojang. Because
none of them shared the result they would quickly hit the limits on the api
causing the conversion to either fail or pause for long periods of time. The
global api cache was a (very hacky) way to force all plugins to share a cache
but caused a few issues with plugins that expected a full implementation of
the HTTPURLConnection. Due to the fact that most servers/plugins have updated
now it seems to be a good time to remove this as its usefulness mostly has
expired.