Update README.md, centered screenshot!

I think screenshot is better when it is centered.
Merge pull request #85 from MaciejCzyzewski/patch-2

Update README.md, centered screenshot!
Update README.md
init tumblr mashup
jquery and global hacks for now just to get it to work, updated scores with pics instead, need to clean up styles
simplifying ui and implementing progress bar as a lot of the old ui doesnt pertain to this image based mode
still need to modularize everything i added but it seems like it works now

. I'm not totally sure if its winnable but it resets correctly. Need to
correct media query css and game messages to fit tumblr theme
normalized a bit of the small / expanded css.

next want to add ability to enter a tumblr blog or pick a random for
your follows if you authenticate
tumblrs favicon and cat gif page
merging tumblr redo