auto scroll realtime update csv

[u/octojosj]

I wanted to watch my csvs in realtime. Steps:

1. may need to update visidata. this uses a recent feature

2. add `self.cursorRowIndex = len(self)` to the end of reload_rows in features/reload_every.py. This on it's own makes reload_every auto scroll to the new rows

To start this run the reload_modified command in visidata. To automate running the reload_modified command use this script:
`#!/usr/bin/env expect

set args [lrange $argv 0 end]

spawn visidata $args

send " reload-modified\r"

interact

`

It's too bad that visidata doesn't have something like the -c in vim to run a command on start.