Using macros and inline function for quick lookup of channel state.
Use channel state lookup macros in channel.c
Using channel state lookup macros in channeltls.c
Using channel state lookup macros in circuitbias.c.
Using CHANNEL_IS_OPEN macro in circuitbuild.c
Using channel state lookup macros in circuitlist.c.
Using CHANNEL_FINISHED macro in connection.c
Using channel state lookup macros in connection_or.c.
fixup! Using channel state lookup macros in connection_or.c.