Response now returns the actual raw soap with the method soap and a nokogiri xml document of it with the doc method
ApplicationResponse's certificate is now an instance method with memoization, remove unnecessary method application_response_as_xml from Response, remove unnecessary if clauses from extract_application_response method, add xml method to utilities
Add to_s methods to Response and ApplicationResponse
Rename ar to xml and add doc method for getting the xml in nokogiri xml format in ApplicationResponse the same way as in Response, rename xml method in Utilities to xml_doc because of name clashes
Add memoization to methods in Response and remove unused constant
ar --> application_request
DanskeSoapRequest methods are private
ar --> application_request
ar --> application_response
NordeaResponse content --> own_signing_cert
Rename application_response attribute in ApplicationResponse to xml
Add constants for commonly used xml namespaces to sepafm.rb
Add decode and canonicalize_exclusively methods to utilities
Response refactoring and formatting

* Use xml_doc method throughout Response class
* Use at instead of at_css
* Use new canonicalize_exclusively method form utilities
* Better code formatting
* Use xml namespace constants from sepafm.rb
ApplicationResponse refactoring and formatting

* Use xml_doc method throughout ApplicationResponse class
* Use at instead of at_css
* Better code formatting
* Use xml namespace constants from sepafm.rb
* Use decode method from utilities
Better code formatting in NordeaResponseTest
Add xml namespace used in Danske Bank's certificate requests to sepafm.rb
Use xml namespace constant from sepafm.rb and add memoization to methods
Add new xml namespaces to sepafm.rb
Add x509_certificate and encode methods to utilities and use them throughout utilities