README.md file needs updating

[Raz]

Describe the bug
Related to issue #184 - README.md file is lacking clarity and user/virtualenv based installation instructions.

To Reproduce
Follow the README.md file as a new user/developer.

Expected behavior
A clearer and more concise README.md file to follow.

Setup

• Python version: 3
• Blimpy version: master
• Operating Systems: Ubuntu 20.04 and Gentoo.

Additional context
Related to #184 - blimpy documentation needs an update.

[dmkunsman]

is this still open?