tests: request_rewrite: Better exception propagation testing.
OpColorizeLabels: Loop over colortable values if there are more labels than the colortable would otherwise support.
graph.py: Bug fix: Correctly handle the case in which the user provides the destination array via slot.get()
request_rewrite: Use a priority queue for request execution order.
request_rewrite: Comment.
request_rewrite: Added interchangable FIFO and LIFO options.
Also, reorganized import statements.