Thusand separator in data sent/received

[nmingotti]

. The proposed change adds a default thousand separator in the "SENT" and "RECEIVED" columns.
. Thousand separator improve quick data readability
. The thousand separator is character: "," , independently from user locale
. The change reduces the number of decimal digits to "1". This is to retain the author original decision to include them.
. When the number is too big to fit a column the "ERR:tooBig" is shown, inviting the user to change scale and see data in the proper format.

[raboof]

I don't strongly care about thousands-separators, but I'm not opposed to it either.

I think we should keep the number of decimals to '3'.

I see some formatting problems. Rather than pointing them out individually, I'd suggest you 'make format'. I have done that for the main branch as well, as it seems we forgot this for some recent PR's. This might introduce some merge conflicts, sorry about that.

[raboof]

Why do you think showing one decimal is better than showing three? Three seems to make more sense to me.

[nmingotti]

Hi, a few collected thoughts on decimals:
. I found nethogs a few days ago and really like it. But, the first thing that was not clear to me on the first run was "that dot is to separate thousands or decimals?". Maybe "B" stands for bit ! etc. etc. A 3 digits block makes (at least me) immediately think of thousand separator. The dot does not help, in central Europe this is a thousand separator.
. In general, it is of scarce interest to show even one decimal for numbers greater than, say 50. It is more noise than information since the error you introduce leaving out the decimal is very little. Still, it is noise that eats a lot of column space.
. Consider "top", there, where decimals are informative it is only 1 decimals, for magnitudes that are expected to be less than 100 most of the time.
. Column are very scarce resource, so if we keep long numbers (no automatic udm adjustment) the choice is between 2 decimals or 2 thousand separators. My preference is to read well the big numbers and forget about the tiny digits dance.