Investigate using toLocaleString for number formatting

[narenranjit]

Modern browsers apparently already have some amount of formatting functions built-in

https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Number/toLocaleString
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/NumberFormat/format

Probably can't replace the existing formatter, but should re-write that to use built-ins where possible.

At the minimum should create a 'locale' converter to allow easy internationalization.