more updates to README.md
more updates to README.md

apigee/apigee-ios-sdk,developerdave/apigee-ios-sdk,RobertWalsh/apigee-ios-sdk,RobertWalsh/apigee-ios-sdk,apigee/apigee-ios-sdk,RobertWalsh/apigee-ios-sdk,pauldardeau/apigee-ios-sdk,pauldardeau/apigee-ios-sdk,apigee/apigee-ios-sdk,developerdave/apigee-ios-sdk,apigee/apigee-ios-sdk,RobertWalsh/apigee-ios-sdk,developerdave/apigee-ios-sdk,pauldardeau/apigee-ios-sdk,developerdave/apigee-ios-sdk,pauldardeau/apigee-ios-sdk,apigee/apigee-ios-sdk,RobertWalsh/apigee-ios-sdk,developerdave/apigee-ios-sdk,RobertWalsh/apigee-ios-sdk,apigee/apigee-ios-sdk,developerdave/apigee-ios-sdk