Revamp README setup instructions.
Revamp README setup instructions.

- Be more explicit.
- Add more information for beginners.
- Add instructions on installing requirements and running the tests.

xguse/trenderbot,xguse/trenderbot,mishin/python-project-template,seanfisk/python-project-template,mishin/python-project-template,shekkbuilder/python-project-template,shekkbuilder/python-project-template,seanfisk/python-project-template