Use NewRandom instead of NewUUID

NewUUID is based on a timestamp, while NewRandom
is based on a PRNG, like it should be.

tokengen.go

@@ -17,7 +17,7 @@ func removePadding(token string) string {
 
 // GenerateAuthorizeToken generates a base64-encoded UUID code
 func (a *AuthorizeTokenGenDefault) GenerateAuthorizeToken(data *AuthorizeData) (ret string, err error) {
-	token := uuid.NewUUID()
+	token := uuid.NewRandom()
 	return removePadding(base64.URLEncoding.EncodeToString([]byte(token))), nil
 }
 
@@ -27,11 +27,11 @@ type AccessTokenGenDefault struct {
 
 // GenerateAccessToken generates base64-encoded UUID access and refresh tokens
 func (a *AccessTokenGenDefault) GenerateAccessToken(data *AccessData, generaterefresh bool) (accesstoken string, refreshtoken string, err error) {
-	token := uuid.NewUUID()
+	token := uuid.NewRandom()
 	accesstoken = removePadding(base64.URLEncoding.EncodeToString([]byte(token)))
 
 	if generaterefresh {
-		rtoken := uuid.NewUUID()
+		rtoken := uuid.NewRandom()
 		refreshtoken = removePadding(base64.URLEncoding.EncodeToString([]byte(rtoken)))
 	}
 	return