added tests for candidate replace() and largestDiagonal().

Also fixes bug with replace() multiple.
Fixes min() test in CandidateTest.
Added tests for getFlight(), getNumPoints() and branch() in BrokenLineOptimizer.
changed toString in Fix, added test.
added compile.debug to ant (useful for testing).
Fixes isFinal(), added test.
added test and a first go at optimize().