rework and clarify the SchedulerRequirements RfC
small tweaks to the doxygen config
Collection of a lot library worthy sources, many extracted from lumiera
priqueue implementation

this adds a minimalistic priority queue based on a binary heap
Add a copy function to the priqueue

by providing a custom copy function one can adjust otherwise non-copyable
elements. This should be used cautionary because dereferencing elements may
poison the cache and thus have some considerable performance impact
(profile this)
cleanup in the priqueue test-code
Import priority queue implementation from Cehteh's library
integrate priority queue: adjust imports and doxygen comments
integrate priority queue: lumiera namespace prefix; unit test pass