enable threading and fix ssl with new dlls

Adds lua-llthreads so that we can get proper threading in plugins.
This enables all kinds of greatness, like easy asynchronous networking,
which we are now going to use in the update checker.
Also fix the ssl dll with one I built myself. Apparently the old one
didn't work on some machines (at least bare Windows XP).
Add a brief yield in manual update check too
Update async.lua

module async instead of old name
update version info