Linux: UI scale is sometimes not 1.0 on non-high-DPI monitors

At the moment, UI scale is calculated on Linux from physical monitor dimensions (obtained ultimately from EDID) and not system scale. The granularity is 0.25, so scale can be 0.25, 0.5, 0.75, 1, 1.25, 1.5, etc. This results in some monitors (in about 107-108 DPI range) to fall into 1.25 scale, which creates too large windows.

Proposed fix is to make the scale more coarse and have scales 0.5, 1, 1.5, 2, etc.

1. Run on a monitor that has 108 or so physical DPI (grep DPI /var/log/Xorg.0.log to find one)
2. Notice too large windows