Inconsistent Quantity.toString behaviour on locales with decimal comma

[exlevan]

When a Quantity is converted to String on locales that use comma as a decimal separator (such as russian or french), the number is displayed differently depending on whether it's close to a whole number or not. For example, 0.0 is displayed as 0,0 units and 0.5 as 0.5 units. This is caused by the code in squants.Platform, which uses both locale-dependent format and locale-independent toString.