Implement iPython like notebook

[ramnathv]

The idea is to have a single column document with editable code cells, just like an iPython notebook. It should allow users to execute a single code chunk or the entire document.

I think this should not be very complicated. In fact, I already have an interactive single column version of the console, with output below, and I should be able to tweak it.

[karthik]

Would also be nice to have output cached so a document can be viewed through something like nbviewer.

[ramnathv]

Yes, that is what I was thinking. So pretty much, just run like you would run knit2html, but modify the default markup, that makes it easy to use javascript to convert the code cells to interactive, and also be able to replace outputs.