wrs_bktr: Test weak recursively simplicial
In kelvinyangli/wrsgraph:

This function tests if a given graph is weak recursively simplicial. If test positive, the given undirected graph is also oriented into a hybrid graph (a graph may contain both undirected and directed edges). This function uses backtracking method to test a graph, so it can be slow for large graphs. It outputs positive if the graph is either chordal or wrs.

1	wrs_bktr(G, D, debug = F)

`G`	A given undirected graph stored in an adjacency matrix format.
`D`	An undirected graph to start orienting with. Coud be set to G.
`debug`	A boolean argument to show steps of the backtracking algorithm.