Size method for bag and set + test size reduction.
Stack top method + test reductions.
Fix top bug + change reset to only clear.
Add size method to the stack.
Implement front and size for the queue.
Remove mem reset from reset operation.
Basic undirected graph impl.
Deque API update + test updates.
Priority queue update + sstack reset optim.
DFS impl + usage. Tests pending.
Readme <- graph + dfs.