refactor calc_og; spider image URLs; fix xpath; add a (broken) expiringcache; loads of other fixes
refactor calc_og; spider image URLs; fix xpath; add a (broken) expiringcache; loads of other fixes

TribeMedia/synapse,TribeMedia/synapse,matrix-org/synapse,TribeMedia/synapse,TribeMedia/synapse,matrix-org/synapse,matrix-org/synapse,matrix-org/synapse,TribeMedia/synapse,matrix-org/synapse,matrix-org/synapse