Andrew remove import all

A recent Plotly error unearthed an `import *` statement that made interpreting the root cause difficult. In an attempt to have that never be an issue again, this PR removes all the `import *` statements.

As a side note, the import * statements were acting on modules with a well-defined `__all__` objects. However, that's not possible to tell from a Traceback, you still just see `import *`.

`__all__`: https://docs.python.org/2/tutorial/modules.html#importing-from-a-package
Same as note above, but for `plotly.plotly.plotly`

```python
>>> from plotly.plotly.plotly import *
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'NoneType' object does not support indexing
>>> from plotly.plotly import *  # this is still OK, but we'd rather users used `py`
```

I believe this is the functionality we want.