New visuals

fixed several issues.

We have:
```
Buffer.nbytes   # size in bytes
Buffer.resize(nbytes)
DataBuffer.size  # size in items
```
There also used to be `DataBuffer.resize(items)`, but I removed this because it was just begging to be misused. Maybe I should resurrect `DataBuffer.resize`, and just use a setter for `Buffer.nbytes` instead of `Buffer.resize` ?