Tables - Proposed syntax

Would it be worth adding table support here? I'm thinking that a | could be a good delimiter here:

```
tests
addition
| a b result
| 1 1 2
| 3 4 7
```

So every line would start with a | and a tab, header row would be down to the individual parser.

The proposal does not name files or tests; start by locating the individual parser mentioned in the issue and reviewing how existing syntax is parsed. Before implementation, settle the table syntax and parser responsibilities, then add support for the agreed form and tests showing that the sample table is parsed correctly.

Written by the indexing model from the issue text.