Description

This MR makes the Currentsource switchable as discussed in #35. Breaking Change: As the current source is now a switchable it starts in the off mode. So all current sources which where not switchable need to be turned on by running the "on()" method before output is generated.

Implements #35

Type of change

Please delete options that are not relevant.

Bug fix (non-breaking change which fixes an issue)
Breaking change (fix or feature that would cause existing functionality to not work as expected)
This change requires a documentation update

Checklist:

I have performed a self-review of my code
I have commented my code, particularly in hard-to-understand areas
I have made corresponding changes to the documentation