Add configuration to allow more use cases

[tillnagel]

Great tool and visualization!

It would be nice if you add some possibility to configure the parsing, for instance:

• Enable other delimiters. At the moment, only commas are accepted. Maybe use d3.dsv and either automatically read the first line, and presume the delimiter, or add some UI for users to select.
• Enable String parsing in quotes. At the moment, your tool splits a value of "with, comma" into two. This allows users - as in your intro example - to quickly find these odd values. But all Strings might be in quotes, and one want to investigate those.

[briatte]

Excellent work, I love it too!

What I would like to suggest is perhaps in line with the previous comment: any way NA values (as text) in numeric could be marked differently? I work with R, so all my CSV files contain such values, which mean "missing" in R. I'm about NA as in

a,b,c
1,2,NA
1,2,3

not as

a,b,c
1,2,"NA"
1,2,"3"