generate example number for country about jsvat

[se-panfilov]

Hi @mathroc

Honestly, that's far beyond of the scope of this library.

I won't do that, and here I will describe why:

• Maybe I could provide hardcoded example for each country, but... some countries might have several different regex patterns, so it's not such clear which on to use;
• I check it in two steps - Regex + math. Even if you would generate string based on regex, what you would do with math? For existed functionality it will be an inverse problem.
• The size of the lib will be much bigger.

So, I'd say it would be a good idea to write another library which can do that, but... Honestly I don't think that this functionality is heavy required, and perhaps some solutions are already here