Use convenience functions in documentations

The examples can be simplified to use the convenience functions offered by the
library.

README.md

@@ -90,19 +90,12 @@ func BeginRegistration(w http.ResponseWriter, r *http.Request) {
 }
 
 func FinishRegistration(w http.ResponseWriter, r *http.Request) {
- response, err := protocol.ParseCredentialCreationResponseBody(r.Body)
- if err != nil {
- // Handle Error and return.
-
- return
- }
-
  user := datastore.GetUser() // Get the user
 
  // Get the session data stored from the function above
  session := datastore.GetSession()
 
- credential, err := webAuthn.CreateCredential(user, session, response)
+ credential, err := webAuthn.FinishRegistration(user, session, r)
  if err != nil {
  // Handle Error and return.
 
@@ -141,19 +134,12 @@ func BeginLogin(w http.ResponseWriter, r *http.Request) {
 }
 
 func FinishLogin(w http.ResponseWriter, r *http.Request) {
- response, err := protocol.ParseCredentialRequestResponseBody(r.Body)
- if err != nil {
- // Handle Error and return.
-
- return
- }
-
  user := datastore.GetUser() // Get the user 
 
  // Get the session data stored from the function above
  session := datastore.GetSession()
 
- credential, err := webAuthn.ValidateLogin(user, session, response)
+ credential, err := webAuthn.FinishLogin(user, session, r)
  if err != nil {
  // Handle Error and return.