fix lua_thread_resume_state to not call lua_resume from a CFunction executing in the same state; lua_thread_done is now unprotected...

merge lua_thread_setup bcak into _lua_thread_start, as everything can be done on the main lua state

implement lua_console_on_interrupt to abort any executing thread

add a console_callbacks::on_interrupt callback triggered by SIGINT while waiting

fix lua_nexus_sleep to use lua_thread_yield_state

implement lua_thread_abort, add lua_thread_yield_state func, and fix lua_thread_resume_state to use protected mode

accept NULL for log function fmt arg

merge lua-threads branch, all lua_console input is now executed in a new lua thread

fix lua_nexus_sleep to use EV_TIMEOUT + misc

fix console to ignore input while waiting, and rename have_input -> have_prompt