Support comma delimiters in amount field of send form

[markmhendrickson]

[kyranjamie]

I'd hold off doing this until we localise the wallet properly. To many, this is 5.210 which adds an ambiguity that isn't there with no delimiter at all.

[markmhendrickson]

Are there English locales that treat the comma as a decimal? If so, I'd agree let's wait. Though if not, it seems consistent with the default language?

[314159265359879]

I would prefer not using delimiting like this, it just leads to confusion and mistakes. Only use . and , as decimal mark

If you want to improve readability use space for delimiting.