Improve readability of README.md

[MichaelCurrin]

Description

• Make massive images sane with width="...px" set on img tags.
• Fix bad grammar. e.g. Create clone ***your forked repository***
• Improve consistency and flow of bold and italics. Single * to _ and remove triple ***.
• Point projects link to a directory in the repo - rather than a full URL on a fork.
• Add tip on Fetch Upstream!

Type of change

Choosing one or more options from the following as per the nature of your Pull request.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Documentation Update

Checklist:

Please tick all the boxes that are fulfilled by your Pull Request.

• [ ] I have named my files and folder, according to this project's guidelines. n/a
• [ ] My code follows the style guidelines of this project. n/a
• My Pull Request has a descriptive title. (not a vague title like Update index.md)
• [ ] I have commented on my code, particularly in hard-to-understand areas. n/a
• [ ] I have created a helpful and easy to understand README.md, according to the given README_TEMPLATE. n/a
• [ ] I have included a requirements.txt file (if external libraries are required.) n/a
• [ ] My changes do not produce any warnings. n/a
• [ ] I have added a working sample/screenshot of the script. n/a