Start of implementation of special "queue" type for depsgraph
Fleshed out more descriptive text for the depsgraph queue type
Creating stub function defines for queue operations based on queue stubs from earlier
Code reshuffling and section labelling
Started drafting some datastructures for the depsgraph queue
Change Depsgraph Queue to use standard data structures
Init/Free Depsgraph Queue data
Size query functions for the depsgraph queue
Finished logic for depsgraph queue push/pop
Some clean work on size of queue
Resort to using pending nodes if nothing available otherwise
Split depsgraph queue defines off into a separate header
Remove dummy priorty queue stubs from stubs.h
Replace queue stubs with real depsgraph queue API