bring swift port up-to-date

the following changes were made:

- updated to latest push-sdk swift port
- update to comply with latest lang changes (as of Xcode beta6)
- sync with features that were added in the obj-c version (progress indicator, calendar popup on datetextfield). Now both share identical feature set
- sync README.md with the obj-c version (removed ref to WFK etc)

done for [AGIOS-220](https://issues.jboss.org/browse/AGIOS-220)