fixed unconnected signal/slot issue for raster mesh conversion
Merge pull request #535 from rinkk/RasterMeshConversionFix

[BugFix] raster mesh conversion connect
Correct comment.
Add numdiff tester.
Move up tester arguments for diff and numdiff.
Merge branch 'test-improvements' into develop
Add cube and square benchmarks for GW.
[ML] Increase LIS's solver accuracy for benchmarks.
Use numdiff in CLI/tests.
[PL] GW: Replace space by new-line in output.