adapt README to code changes
adapt README to code changes

sfeast/cordova-mixpanel-plugin,damienfa/cordova-mixpanel-plugin,samzilverberg/cordova-mixpanel-plugin,samzilverberg/cordova-mixpanel-plugin,Frugl/cordova-mixpanel-plugin,damienfa/cordova-mixpanel-plugin,sfeast/cordova-mixpanel-plugin,samzilverberg/cordova-mixpanel-plugin,Frugl/cordova-mixpanel-plugin