Direct editor

[sameersingh]

Provide an easy grammar to allow the whole specification of the complete notebook in a single format. For example,

{{h1
Example
}}
This is an example markdown cell. We can include math below:
{{latex
\alpha + \beta = \gamma^3
}}

At the very least, we should have an alternate "editor" that just takes the above and writes out the notebook file (first version can just be java). But in future, we can perhaps have a side by side view which autosaves and renders periodically.

[riedelcastro]

I wonder whether we should just think of the whole notebook as a single markdown file? Markdown with interactive/executable code blocks. We would only need a special mark-up for executable scala code. Maybe something like

### Vector-based
Wolfe uses FACTORIE to optimize the objective in
```xscala
val w = argmin ...

One could even imagine editing the whole notebook in the ACE markdown editor, and extend the ACE editor to inject compilation results into the editor box. (Along with a proper compiled/static view).

[sameersingh]

With the extensive keyboard shortcuts and layout support afforded by #51, this is mostly unnecessary, except for pre-processor plugins support.