Code clean-up. No functional change.
Added twiddle factors to graph.
However, they need clean-up.
Added `getTwiddleStrs' to LogTree class.
Need to track twiddle factor accumulation and print them only with
original input list elements.
Added two simple test cases to Main.hs.
Checking in, before reviewing tags for presentation labeling.
treeviz 0.0.5
Twiddle factors now shown in graph, for DIF stages.