Hug

- Fixed issue 834: Bug in some cases when introspecting local documentation.

- Improved CLI multiple behaviour with empty defaults
- Improved CLI type output for built-in types
- Improved MultiCLI base documentation

- Fixed issue 815: map_params() causes api documentation to lose param type information
- Improved project testing: restoring 100% coverage

- Fixed issue 808: Problems with command line invocation via hug CLI
- Fixed issue 647: Support for arbitrary URL complexity when using CORS middleware
- Fixed issue 805: Added documentation for `map_params` feature
- Added initial automated code cleaning and linting partially satisfying [HOPE-8 -- Style Guideline for Hug](https://github.com/hugapi/HOPE/blob/master/all/HOPE-8--Style-Guide-for-Hug-Code.md#hope-8----style-guide-for-hug-code)
- Implemented [HOPE-20 -- The Zen of Hug](https://github.com/hugapi/HOPE/blob/master/all/HOPE-20--The-Zen-of-Hug.md)

- Fix issue 798 - Development runner `TypeError` when executing cli

- Fixed issue 794 - Restore support for versions of Marshmallow pre-2.17.0