Support for Styles

[patrickomatic]

It would be great to define "styles" up in the code section:

header := [[t = bold / halign = center / valign = center / fs = 20]]

and then use them in the CSV section:

...
---
[[#header / var=foo]],bar,baz

Outstanding Questions

• I like the #header syntax using the hash but does it conflict with the future plans to make the row comment-out-able? We'd use the # for that. But it would have to be the first non-whitespace character on the line, so it doesn't really conflict per-se
• For the definition syntax foo := [[ ... ]] - can we think of anything better? It seems kinda unsymmetrical that we use [[ and not ![[ but whatever I guess...