[python-client] Add model default values (#1776)

* Adds two models to the v2.0 spec, uses examples as defaults in python client

* Adds array default and type_holder_default and type_holder_example tests

* Re-generated python security client with ./bin/security/python-petstore.sh

* Changes comment text, rebased master

* Updates client + server samples

* Adds missing samples updates

* Changes python client to look for true or false with booleans in toDefaultValue

* Changes boolean casting to use Boolean.valueOf

* Adds deserialization fix for python tests

* Changes Mock to namedtuple in python deserialization tests

* Actually remove unittest.mock

samples/client/petstore/php/OpenAPIClient-php/docs/Model/TypeHolderDefault.md

@@ -0,0 +1,14 @@
+# TypeHolderDefault
+
+## Properties
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**string_item** | **string** |  | [default to 'what']
+**number_item** | **float** |  | 
+**integer_item** | **int** |  | 
+**bool_item** | **bool** |  | [default to true]
+**array_item** | **int[]** |  | 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+

samples/client/petstore/php/OpenAPIClient-php/docs/Model/TypeHolderExample.md

@@ -0,0 +1,14 @@
+# TypeHolderExample
+
+## Properties
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**string_item** | **string** |  | 
+**number_item** | **float** |  | 
+**integer_item** | **int** |  | 
+**bool_item** | **bool** |  | 
+**array_item** | **int[]** |  | 
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+