chore(release): 5.0.0 [skip ci]

# [5.0.0](v4.4.5...v5.0.0) (2019-10-04)

### Bug Fixes

* Handle multipart form sending from Visual Recognition and others ([8651e0d](8651e0d))

### Features

* **Assistant v1:** Add constructor for external auth config and fix serialization bug ([7790e43](7790e43))
* **Assistant v2:** Add constructor for external auth config and fix serialization bug ([82a8470](82a8470))
* **Compare and Comply:** Add constructor for external auth config and fix serialization bug ([ed19cf7](ed19cf7))
* **core:** Add authenticator for bearer tokens ([de3cdba](de3cdba))
* **core:** Add base classes around token auth ([3bb0202](3bb0202))
* **core:** Add class for authenticating with external credentials ([9498af7](9498af7))
* **core:** Add new base authenticator and modify interface ([d45ad8a](d45ad8a))
* **core:** Add superclass methods to get mapping between SDK and API prop names ([87c79b7](87c79b7))
* **Discovery:** Add constructor for external auth config and fix serialization bug ([e3c8231](e3c8231))
* **IBMWatsonJSONUtil:** Add method to replace JSON keys in a model being serialized ([b3fe6b5](b3fe6b5))
* **Language Translator:** Add constructor for external auth config and fix serialization bug ([b0295b7](b0295b7))
* **Natural Language Classifier:** Add constructor for external auth config and fix serialization bug ([1c11430](1c11430))
* **Natural Language Understanding:** Add constructor for external auth config and fix serialization bug ([befc99a](befc99a))
* **Personality Insights:** Add constructor for external auth config and fix serialization bug ([8d635f2](8d635f2))
* Replace property names as necessary when getting response back from API ([9d1a5f4](9d1a5f4))
* **Speech to Text:** Add constructor for external auth config and fix serialization bug ([3cc16fd](3cc16fd))
* **Text to Speech:** Add constructor for external auth config and fix serialization bug ([2ed7e7f](2ed7e7f))
* **Tone Analyzer:** Add constructor for external auth config and fix serialization bug ([1af8d78](1af8d78))
* **Visual Recognition v3:** Add constructor for external auth config and fix serialization bug ([a97436d](a97436d))
* **Visual Recognition v4:** Add constructor for external auth config and fix serialization bug ([fd54e14](fd54e14))
* **Visual Recognition v4:** Add newly generated service ([fc497e9](fc497e9))

### BREAKING CHANGES

* **Discovery:** This commit removes the testConfigurationInEnvironment, queryEntities, and
queryRelations methods