paste events sent to stdin when appropriate
paste events sent to stdin when appropriate

Previously constituent events of a paste event were always
processed normally, with no conditional checking for whether
stdin currently had focus. Now this is checked, events are directed
there until it no longer has focus.

wevial/bpython,kdart/bpython,wevial/bpython,aktorion/bpython,kdart/bpython,aktorion/bpython