grid api

I was thinking the columns would max out at like 10 characters. I like the `<` because they help differentiate between entries:

```
Grid: [Column "column 1": [1, 2, 3], Column "column 2": ["a", "b", "c"]]
```

is hard to read. But there might be a better representation. In any case, I think its nice when people go:

```
>> grid
```

We show the names, and a little bit of the data