This may break backwards compatibility in some cases. For example, the FreeDiskSpace measure treated only `Type=1` as true and `Type={0, 2, 3, ...}` as false. Now `Type=0` is false and everything else is true like with most other boolean options.
This change is part of making the Libray project more testable. The old g_Rainmeter global pointer has been replaced with a GetRainmeter() function to guarantee that the object exists in some state.