Propagation of signed zeros when multiplying by a negative scalar vs. an `EvenCliffordNumber` equal to that scalar

[brainandforce]

This is a significant issue that can arise when multiplying a Clifford number by a negative scalar as opposed to an EvenCliffordNumber equal to that scalar:

julia> x = EvenCliffordNumber{VGA(3),Float64}(0, 0, 6, 9)
4-element EvenCliffordNumber{VGA(3), Float64}:
6.0e₁e₃ + 9.0e₂e₃

julia> -x == x * EvenCliffordNumber{VGA(3),Float64}(-1)
true

julia> isequal(-x, x * EvenCliffordNumber{VGA(3),Float64}(-1))
true

julia> -x === x * EvenCliffordNumber{VGA(3),Float64}(-1)
false

Part of this issue is due to the behavior of signed zero under addition: 0.0 + (-0.0) === 0.0.