Update README.md [ci skip]
Escape newlines
Added helper methods for Response class
Merge branch 'master' into response_status
Update samples [ci skip]
Update samples
Helper methods to generate express checkout url
Added ipn_valid? method to validate IPN message
Merge branch 'response_status'
Update version to 1.98.2
Merge branch 'rel-1.98.2' into stable