Add slice and factorization of posterior samplers
The testsuite runs fine with the current state. TBD:
- Dealing with
adaptive_metropolis_hastings
which now is broken as it relies onrandom_walk_metropolis_hastings_core.m
which is supposed to be deleted soon and does not run anymore after the changes (@MichelJuillard @stepan-a Do we have a mod-file triggering this part of the code somewhere)