Add more text and information on the page.

[StephenXie]

We should have more information on the page to inform users what this site is for and what they should do to calculate their GPA. Include some text from the wiki page and/or hackathon submission.

[StephenXie]

#39

[StephenXie]

First, we should move the information down below the calculation part. Then, we can have FAQs listed below the description.