link activation triggers to activation

The main changes are exactly as advertised: calling smem_lti_activate in
various places, checked by the activation-triggers option. There are a
number of smaller changes as well:
* removed activation unification options (reverting 41b97ad7970cedb593647caeb34308116a4458de)
* removed activate-on-query options (subsumed by activation-triggers option)
* refactored smem storage, so the augmentation thresholding makes more sense

TODO:
* rule-condition option for activation-triggers is not implemented
* remove printouts