Portray

- Upgraded mkdocs-material & pymdown-extensions

- Bump pdocs dependency to include some package inclusion improvements.
- Speed up doc copying by only copying markdown files.

- Fixed [Issue 43](https://github.com/timothycrosley/portray/issues/43) - Automatically remap `-` to `_` when attempting to auto-determine module name.
- Added `extra_markdown_extensions` config option, to enable adding markdown extensions without having to redefine default set included by portray.

- Potentially backward compatibility breaking performance optimization: portray now only renders root project files + the specified documentation directory + any specified extra_dirs.
If a previously utilized file used to be auto included, but is no longer, you can force its inclusion by adding its directory to `extra_dirs.`
For many projects, this change results in a significantly smaller output size and significantly faster documentation generation.
- Implemented [Issue 31](https://github.com/timothycrosley/portray/issues/31) - Improved repository auto-discovery and formatting.
- Fixed [Issue 33](https://github.com/timothycrosley/portray/issues/33) - Improving usability and documentation of nav customization.
- Added many additional test cases - Reaching 100% test coverage.
- Added indicators that let users know what step is occurring during documentation generation.

- Fixed [Issue 23](https://github.com/timothycrosley/portray/issues/23) - A confirmed regression from moving to `pdocs` that caused root modules to not be auto included.

- Fixed a bug specifying the output dir for `as_html` command from the command line.
- Updated to use Python3.6+ style variable annotations.