Use single quotes in layout-test.js
Correctly preserve edge direction in cyclic graphs

A regression was introduced that caused backedges to be left in a
reversed state after layout finished. This was almost certianly
introduced when the acyclic function was moved to the rank function in
38804b49a27a112f20da4122169d7f1c9e62d5bf.
Also commit lib/version.js as post-release step
Prep v0.3.8 release