add viewers for different file types

[bwalsh]

#CSV/TSV

import pandas as pd

url = "https://A-SIGNED-URL/somefile.csv"
c = pd.read_csv(url)

https://github.com/man-group/dtale/blob/master/docs/EMBEDDED_FLASK.md

#VCF

https://genome.ucsc.edu/goldenpath/help/vcf.html

Move both the compressed VCF file (my.vcf.gz) and tabix index file (my.vcf.gz.tbi) to an http, https, or ftp location.Note that the Genome Browser looks for an index file with the same URL as the VCF file with the .tbi suffix added. If your hosting site does not use the filename as the URL link, you will have to specifically call the location of this .vcf.tbi index file with the bigDataIndex keyword. This keyword is relevant for Custom Tracks and Track Hubs. You can read more about bigDataIndex in [the TrackDb Database Definition page](https://genome.ucsc.edu/goldenpath/help/trackDb/trackDbHub.html#bigDataIndex).