[WIP] - Discovery

```Python
In [1]: from datashape.discovery import discover

In [2]: data = [{'name': 'Alice', 'amount': '100'},
   ...:         {'name': 'Bob', 'amount': '200'},
   ...:         {'name': 'Charlie', 'amount': '300'}]

In [3]: discover(data)
Out[3]: dshape("3 * { amount : int64, name : string }")
```