Is your feature request related to a problem? Please describe.
When working with a big piece of text, I sometimes scroll down and copy some text into another tab. When switching back to the first tab, both the input and the output pane is back on top. So I don't know where I was working just now.

Describe the solution you'd like
After tab switching, scroll position should be remembere

Describe the bug
Danfojs does not throw correct error when more than one key specified in the merge function

To Reproduce
Steps to reproduce the behavior:

1. Go to 'https://playnotebook.jsdata.org/'
2. load danfojs version 0.2.4 using load_packages
3. run the following code:

let data = [['K0', 'k0', 'A0', 'B0'], ['k0', 'K1', 'A1', 'B1'],
            ['K1', 'K0', 'A

Anki shortens filenames that are too long in the latest versions, but only when a user runs Check Media. If they have already created a repo using Brain Brew then their old media will still be there. Seems to me there are a few issues here:

Warn users about long filenames

Make sure people are not caught out by this by detecting when a media filename is too long. Then users know what to do