Add extensive testing for zero-width `Logic`s and `LogicValue`s

[mkorbel1]

Motivation

There have been multiple bugs found related to zero-width Logics and LogicValues.

Desired solution

Add a bunch of tests covering behavior of things when the are zero-width, both functionally and for synthesis.

[mkorbel1]

See #57

[mkorbel1]

Some things to consider:

• Unary operations (in gates and on LogicValues) need to probably throw an error when called on a 0-width signal

[dmetis]

I can take this