fix(webhooks): sort webhooks by created, use angular-filter for sorting object
fix(bootstrap): upgrade angular-ui-bootstrap
feat(private-messages): start implementing private messaging (includes blocking). Start experimenting with reflists for PMs, instead of arrays
Merge pull request #4260 from HabitRPG/PMs

Private Messaging
Ensure that a paypal payment is processed no more than once, also keep track of the user in the payment object rather than in session
Begining the implementation of pay and subsciption using bitpay
Now able to process a payment using bitpay