Commit Briefs
libdraw: add visibleclicks mode
R=rsc http://codereview.appspot.com/6501137
In non-blocking recv functions in libmux and libdraw,
distinguish between "cannot receive without blocking" and "EOF on connection". In libmux, do not elect async guys muxers, so that synchronous RPC calls run in the main event loop (e.g., in eresized) do not get stuck. Fixes problem reported by Lu Xuxiao, namely that jpg etc. would spin at 100% cpu usage.