Set a value on the context object by path, will build the object as it goes
*nb not idempotent will change the value passed in, see below for idempotent call
context object to set value on
property path to value
value to set
the root context again (for convenience)
Set a value on the context object by path, will build the object as it goes
*nb not idempotent will change the value passed in, see below for idempotent call