Add decimal separator force to "." dot for frequencies translation on…

[Artemia76]

On French Computer, locale use the comma as decimal separator. This make rig exchange translate frequencies without the decimal part { 14,236 -> 14.000) } by using wxWidget::Format when using Frequency reporter

I add a small check and force locale for numeric decimal separator to dot "." to avoid

[tmiw]

Thanks for this code change. I'm not comfortable with just forcing C locale for number processing, especially when this behavior would likely be different from other applications on this system. I created an alternative PR (#561) that updates the frequency list to display properly for the user's current locale. For example, with this PR and forcing LANG to be fr_FR.utf8, the frequency list now looks something like this:

Let me know how that works for you. If that solves your issue, we'll go ahead and close this PR.

[tmiw]

Looks like #561 is good so I'm going to go ahead and close this PR. Let me know if you have any questions.