Added Smalltalk section to index.html

[mumez]

Since 'Smalltalk' is long. I also swapped the list order with 'Go' (for
balancing layout).

[frsyuki]

Great. Welcome to MessagePack project!
Let me know if you need a github repository in the msgpack organization on GitHub. I recommend you to move your repository for users to make it easy to find your code, if you don't have any considerations to move the current repository. It's also a good idea to use GitHub Pages to host API reference.
Additionally, we're working on updating the way to use shared resources. Please have a look at this documentation: https://gist.github.com/2892856

[mumez]

I've prepared for moving MessagePack Smalltalk main repository from Google Code to GitHub. So, could you kindly add 'msgpack-smalltalk' as an official repository? Preview is here: https://github.com/mumez/msgpack-smalltalk.

[frsyuki]

Great! I created an repository. Please push your code: https://github.com/msgpack/msgpack-smalltalk