Improvement: Add sensible component default values for sliders

[E3V3A]

As an improvement to prevent unexpected and nonsensical results when adding a slider to components, I suggest to add the components default values (as found under the components Edit menu), also to the default slider range.

In this respect I think the following function need to be modified to also accept (or take) other default values.

    Adjustable(CircuitElm ce, int item) {
	minValue = 1;
	maxValue = 1000;
	elm = ce;
	editItem = item;
}

Such an implementation would partially address issues such as:

• issue Broken MOSFET behaviour #301
• issue MOSFET model missing parasitic diode #243

[pfalstad]

fixed