BugFix: Meters not showing negative values.
Circuit: Add Non-Linear Accuracy property (volt. reg.).
Circuit: Add Non-Linear Accuracy property.
Mosfet: change model to current-based.
Meters: Avoid continous update.
Some cleaning
Add variable voltage range to Plotter.
BugFix: Volt Regulator not sinking current from source.
BugFix: Probe values not rounding porperly
BugFix: Meter values not rounding porperly
