Made the README a little prettier

[sdushantha]

trafficstars

Awesome project! I am pretty sure present will be used by many people in the near future.

I made some formatting changes to the README to make a bit more prettier.

Changes I made:

• Replaced the previous logo with the first frame from your demo gif (feel free to change the size, wasnt able decide on it)
• Centered the shields
• Added a table of contents
• Remove the gif about codeio for now...

I really liked the gif about codeio but wasn't sure if it looked good right under the main demo gif. Maybe you could add a section which shows off some neat features of present? Or you could merge the demo gif and codio gif together.

Let me know what you think of the changes I have made :)

[vinayak-mehta]

Thanks for the PR @sdushantha! I tend to keep READMEs for all my projects similar. Will review the changes and see what all I can change in the other READMEs sometime this week :smile: