Table support

[lilactown]

currently, it appears that tables are unsupported, e.g.

| Name  | Age |
|-------|-----|
| Alice | 32  |
| Bob   | 28  |

[lishaduck]

Copying this over for posterity:

Tables are really really hard to implement correctly. The behavior when editing really isn't well scoped out either, how exactly should it behave? Obsidian, for example, just uses a WYSIWYG editor for tables. Of course, if you want to give a crack at it, feel free, but just be aware that it's not as simple as it seems.

Originally posted by @lishaduck in #88