added setting to allow logging of tracebacks for exceptions that occurred in Lua callbacks (disabled per default to avoid spamming the log with InvalidArgumentExceptions and the like); moved argument parsing and result pushing to extended lua state and added capability to push maps as tables, meaning callbacks can now return maps, too
grabbing screen touch coordinates on the client side and sending them as a click to the server to avoid loss of accuracy (block activation events only have a resolution of 16x16 apparently). closes #57. again.