Swift ios7

the port that supports iOS 7 target too, utilising the objc-c bridge technique as described in the ML post:
http://aerogear-dev.1069024.n5.nabble.com/aerogear-dev-Swift-running-on-iOS-7-Observations-td8684.html

further have switched back to use the deprecated UISearchDisplayController instead of iOS 8 UISearchController for the search bar functionality so it's available in both versions.

as described in the ML, I am -1 on merging this PR

Let me know your thoughts