dispatch: unroll mro computation to make it more palatable

test: rename test for clarity

doc: add a small bibliography

test mro, refactor next_method/call_next_method, method decorator accepts tuple as type specifier argument for multiple registration

use ambiguity check from gvr's overloading.py, remove useless test

turn back mro computation into GF parameter

use generators, cleanup & simplify a bit

[tests] diamond inheritance & next_method, ambiguous case

remove tuple around function in func table

re-add next-method support

remove unused table element

trim down a bit, add an internal signature/method cache, add a test

initial generic function/multimethods package based on David Mertz multimethods.py