Reorganized the environments page to flow better.

- Added details about how to set the environment for an application
- Added details about setting the environment for Oil
- I updated the information regarding server environment variables as stevewest suggested. Let me know if this is still inaccurate. 

Signed-off-by: Zechariah Campbell
Ok, I changed that. I committed the change. It looks like it was automatically added to this pull request. Is that correct or am I reading github wrong?