Special characters like '#' did not get converted properly on
transformations from/to file path, URL and URI. Added some convenience
methods in URLUtil. Added unit-tests for that with some explanations in
code and little in comments.
Also extended methods and test-parameter for IT-tests.
I will do some more testing, because currently it is unclear whether
this entirly fixes #35 [CC-39]; but the described buggy result was
exactly the same in my tests.