Add multiple inheritance support to Perl client (#1681)

* add multiple inheritance support to perl client

* remove allof test from fake petstore

samples/client/petstore/perl/docs/DefaultApi.md

@@ -0,0 +1,54 @@
+# WWW::OpenAPIClient::DefaultApi
+
+## Load the API package
+```perl
+use WWW::OpenAPIClient::Object::DefaultApi;
+```
+
+All URIs are relative to *http://petstore.swagger.io:80/v2*
+
+Method | HTTP request | Description
+------------- | ------------- | -------------
+[**foo_get**](DefaultApi.md#foo_get) | **GET** /foo | 
+
+
+# **foo_get**
+> InlineResponseDefault foo_get()
+
+
+
+### Example 
+```perl
+use Data::Dumper;
+use WWW::OpenAPIClient::DefaultApi;
+my $api_instance = WWW::OpenAPIClient::DefaultApi->new(
+);
+
+
+eval { 
+    my $result = $api_instance->foo_get();
+    print Dumper($result);
+};
+if ($@) {
+    warn "Exception when calling DefaultApi->foo_get: $@\n";
+}
+```
+
+### Parameters
+This endpoint does not need any parameter.
+
+### Return type
+
+[**InlineResponseDefault**](InlineResponseDefault.md)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+ - **Content-Type**: Not defined
+ - **Accept**: application/json
+
+[[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
+