Invalid JSON number error in some locales.

[jcoffland]

Just a minor remark: by default, on my workstation the locale is usually set to fr_FR.UTF8, which has a comma in place of the decimal point, and it produces an error in the examples (invalid JSON number): I have to switch to a different locale, e.g. en_US.UTF8.

Originally posted by @thierry-FreeBSD in #389 (comment)