Reordering

Created a library Reordering which is ment to be an alternative for Binary and Continous.
Added the example traveling_salesman.hs to demonstrate how it works.

There is administrative work to do: I couldn't manage to import and export the functions the way I wanted. Thats why the example is in the wrong directory. Sorry, but I am still learning.
It should be moved to Tests/Internals/TestPermutation.hs (Tests.Internals.TestPermutation) module.
Tests are built only when `--enable-tests` is given on `cabal configure`. For normal library builds tests are not built so we may remove HUnit and QuickCheck from the dependencies of the normal build.