update(math): group digits

[mikigoalie]

thought it'd be a good idea to include this in math lib

[mikigoalie]

Credits for the formatting goes https://stackoverflow.com/questions/10989788/format-integer-in-lua

[thelindat]

The number type-check is san issue, if say you want to group "$10000".
Then there's the issue of math.floor, because 1000.347 becomes "1,000". Of course, removing it results in bad formatting as "1,000.,347".

This one from lua-users is more robust https://lua-users.org/wiki/FormattingNumbers.

function comma_value(n) -- credit http://richard.warburton.it
	local left,num,right = string.match(n,'^([^%d]*%d)(%d*)(.-)$')
	return left..(num:reverse():gsub('(%d%d%d)','%1,'):reverse())..right
end

[mikigoalie]

hawaii weather pr
The use dot param is probably useless, lmk if you want it to be removed. Just thought it'd be a good idea to have keep it there if anybody needed dot instead of comma

[thelindat]

hawaii weather pr

????

[thelindat]

might as well be divider or seperator as the arg (not useDot), and then just do '%1' .. (divider or ',').