Align columns better with values padded up to 12 digits

[zptro]

• Align columns better with values padded up to 12 digits
• Restrict number of significant digits to 7, larger numbers as exponents

[johpiip]

When decimal numbers are rounded to 7 significant digits, trailing zeros are dropped. This can be verified in workforce_accessibility_per_area.txt where espoo_vant_kau 3993.18506 becomes espoo_vant_kau 3993.185 (7 significant digits = 7 digits) but helsinki_cbd 4571.64987 becomes helsinki_cbd 4571.65 (7 significant digits = 6 digits because last one is rounded to zero). Is this intentional? Both ways are fine by me. (Of course, dropping zeroes may imply that they are not signicant when they actually are...)

Edit: corrected numbers.

[zptro]

Should ask users if they want this change or not.

[johpiip]

@zptro My comment in Teams was about whitespaces but my comment in this PR was about significant digits. I like the idea of explicitly rounding to seven significant digits but I commented on trailing zeros. :)

[zptro]

@zptro My comment in Teams was about whitespaces but my comment in this PR was about significant digits. I like the idea of explicitly rounding to seven significant digits but I commented on trailing zeros. :)

Yes, maybe I could do a separate PR, changing %1.5f into %.7g.