moved some generators to rafter_gen
set config to vstruct instead of list
updated step-by-step introduction to use vstructs
Revert "do not overwrite vote if it exists"

This reverts commit e2dad555566fa1302b59a10dcd8a6ad835e44dcd.
store instead of append
rafter_config_majority: for regression testing
regression test for quorum_max with majority voting structure
test quorum as well
use store instead of append
rewrote prop_majority
use rafter_voting:member