DocFix

Some proposed tidying of README file. Because it’s Markdown I’ve turned all the links into clickable links, which tidies them up a bit and saves space. I’ve also tweaked the capitalisation to match each other, and I’ve tweaked the Homebrew instructions to remove the unnecessary invocation of ``` --Framework ``` (Homebrew’s Python builds a Framework naturally, it doesn’t need invoking).

Not trying to be an arse here; If you like the document how it is, I apologise for proposing changes to it, but hopefully these proposed changes will be useful to you.