Echotime requires Tuples to be homogeneous

[StevenWhitaker]

With the current definition of Echotime, one can't pass in a Tuple with various element types, so, e.g., (0, 2.3) will throw an error. This is because of the <: in NTuple{N,<:T}; removing <: would allow for (0, 2.3).

Not sure if you intended to force all the types of the Tuple elements to be the same, but if not, it should be an easy change.

[JeffFessler]

My intension is to ensure that units are handled correctly:

using Unitful: ms
et = (0, 2.3ms)
et isa NTuple{2,<:Number} # false, as intended
et isa NTuple{2,Number} # true, which will cause downstream problems with incompatible units

I use oneunit(Te) in a few places...

I am open to other suggestions, but I don't want to have a package dependence on Unitful.

I just realized that [0, 2ms] isa Vector{<:Number} holds, so I am enforcing it more strongly for tuples than for vectors. Hmm.