Clearer parameters in client-scripts

Uses longer names for the parameters in the tests-scripts closer to the
recommendations of PEP8.
Much faster factory-method

Double implementation. This one chosen from implementation by Emil Eriksson. Should resolve classes in constant time when the cache is populated.
Merges two different implementations for the same module
Better docstrings for some oauth2 checks
Moves ExceptionWrapper to base-class

As this is used by both oic- and oauth2-scripts this prevents two
implementations of the same class.
Updates the handling of Fatals in OAuth2-testclient

Now prints trace from exception instead of empty trace.

This is probably not the intended behavior but makes errors easier to
debug.
Merge pull request #5 from asheidan/refactor/merge_upstream

Clearer documentation and moving classes used in both protocols