Make README.md more explicit

[cuongdo]

Checklist:

• [x] Code contains relevant tests for the problem you are solving
• [x] Code has been formatted with autopep8 --in-place --recursive --a --a .
• [x] Ensure all new and existing tests pass
• [x] Update any relevant READMEs and docs
• [x] Submit to the develop branch instead of master

Description:

While chatting with @micahalcorn, it became clear that following the instructions for running the bridge server assume some Python knowledge. These tweaks to README.md reduce that.