Add internationalization to gtk-freq-knob decimal separator

[nsdecicco]

Previously, the thousands place separator for gtk-freq-knob was hard-coded as the decimal point (".").

Make the following changes:

• Modify gtk-freq-knob.c to mark this string for translation.
• Add "translations" for each currently supported language.

Translations are made according to the Wikipedia article on decimal point separators.

Comma	Decimal point
UK English	Czech
US English	Danish
Thai	German
	Greek
	Spanish
	Finnish
	French
	Indonesian
	Italian
	Lithuanian
	Russian
	Ukrainian

To keep the commit from being overly large, even though the actual delta of the .po files was quite large (as these have not been updated in 3 years), I added to the commit only the POT generation time change and the addition of the "numeric thousands separator" translations.

[davidfdzp]

Please, consider that Spain is trying to converge with Mexico in the use of dot to separate decimals, even though there is a lot of inertia to use the comma.

[nsdecicco]

Hi @davidfdzp,

I opened a corresponding issue (#273) for this pull request, in which user @wkitty42 pointed out that an alternate (and better) mechanism exists for determining the correct thousands separator to use in the form of the lconv struct.

So, I went ahead and force-pushed a new commit (cca19a18) which uses this new mechanism.

Please let me know what you think.

Thanks,

Nick

[csete]

Thanks for the update @nsdecicco. I have merged the patch.

[nsdecicco]

@csete Thanks for getting this merged!