Duplicate rules returned by create_rule_generator/3

[macabot]

ArgumentMap.generate_amap_set/1 returns argument-mappings for more arguments than necessary.
For example:
generate_amap_set/1 returns both ({1:1, 2:1} {1:1, 2:1}) and ({1:1, 2:2}, {1:1, 2:2}). If these are applied to the formulasets (snake 1) and (bites 1 2), then the rule [(snake 1) (bites 1 2)] --> (snake 1) (bites 1 2) is created twice.