Solution verified correct against jaybruce1998's test suite at (https://www.codewars.com/kata/5c1d796370fee68b1e000611/train/java).
Loopover.solve() will reliably solve any Loopover puzzle with dimensions between 2x2 & 9x9 (inclusive).
LoopoverTestSuite() tests Loopover against 1000000 random boards & 13 pre-defined boards.