Numerical Problems with `UInt` waveforms

[theHenks]

In case you are loading a RDWaveform which consists of Integers, most filter code in RadiationDetectorDSP fails because it wants to return Int types for each sample after the filter is applied.
So far, we convert the waveforms by something like this:

wvfs = shift_waveform.(wvfs, 0.0)

There should be a more elegant solution than this.

CC @fhagemann

[fhagemann]

First thing I would think of: limit the filters that require floating point precision to floating point precision
(<:AbstractFloat instead of <:Real, <:Union{<:AbstractFloat, Quantity{<:AbstractFloat}} instead of RealQuantity)

[oschulz]

JuliaPhysics/RadiationDetectorDSP.jl#54