Function globals globals setlistener

Wrapper for the _setlistener function. Takes a property path string
or props.Node object in arg[0] indicating the listened to property,
a function in arg[1], an optional bool in arg[2], which triggers the
function initially if true, and an optional integer in arg[3], which
sets the listener's runtime behavior to "only trigger on change" (0),
"always trigger on write" (1), and "trigger even when children are
written to" (2).