change API from parameter list to parameter dict

[SimeonEhrig]

During my work on the unit tests, I found out that the unit test framework execute tests in parallel via multithreading. This is problematic, because the generator is not thread safe, because it use the global variable param_map to map a parameter name to an index. There is no easy way to disable multithreading. So the problem cannot be solved easily. In the meantime, I found out, that the allpairspy pairwise library supports OrderedDict. If I replace the list input with a OrderedDict, the param_map variable becomes obsolete and the generator is thread safe. Also API and functions becomes much easier.

The disadvantage of the approach is a lot of work and an API break. So this issue moves the library to version 2.