v4.0.0rc1 - Major code base refactoring and bug fixes

This release is a major codebase refactoring, in the hope to facilitate future features and contributions.
It also contains many bug fixes that were the consequence of a mix of code from me, and the original author of manim-presentation.

With the 4.0.0 release, I hope to only bring stable changes in the future, in pair with a well documented tool.

What's Changed

• chore(README): upgrade documentation in README by @jeertmans in #13
• fix(cli): previous presentation starts last slide by @jeertmans in #14
• feat: large "present" feature refactoring by @jeertmans in #15

Full Changelog: v3.2.4...v4.0.0rc1