initial Ios compatibility

Added code to start the (iOS debugging proxy)[https://github.com/google/ios-webkit-debug-proxy], which we assume is installed. Created an alternate method for calculating OnLoad/DOMContentLoad times based on the corresponding events in the "Page" domain of the remote debugging protocol because safari does not have window.performance. However, the times do **not** seem to be correct. This will have to be fixed later. Also fixed some user agent parsing code for iOS.