fix activity string
Merge commit 'a6bee11bf906c30f9bf61ccf265b8988457c00da'

# By Simon Whitaker (5) and Stephan Diederich (1)
# Via Simon Whitaker
* commit 'a6bee11bf906c30f9bf61ccf265b8988457c00da':
  Add new icon for iOS 7 (retains original icon for iOS <= 6)
  Updated image URL
  Turn on receiver-is-weak warnings
  fix warning
  Make the demo app universal
  Update README.md