Merge pull request #8 from endJunction/test-improvements

Test improvements
Install numdiff on travis.
Use the right diff tool.
Merge pull request #529 from bilke/test-improvements

Improvements for testing with external data
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.
Merge pull request #536 from endJunction/SimpleBenchmarks

Simple benchmarks
[BL] Start CPUTime and RunTime timers at creation.
[PL] GW: Time solve().
Timing and memory scripts.
Logog level ALL.