Allow for subscriptions to auto-renew

--HG--
extra : amend_source : 6e5df2d23fbd8131a7b6d05cef1a181448ec8e41
Better threading model

Try to cancel subscriptions on system exit

--HG--
extra : amend_source : 5e4ee988d6a20b8e96dd43f59e0c0d1c790ffd50
Merge pull request #179 from lawrenceakka/renewing_subs

Renewing subs