[WIP] Types extension

[MartinuzziFrancesco]

This PR is meant to extend the package to return output with matching typing of the given input data. Specifically I am adding the flexibility to all functions to handle Float64 as well as Float32 and Float16.

This is PR is a heavy work in progress at the moment, I'm mercilessly dispatching on all functions that need changing, but I think at the end there's going to be redundant code, I'll sweep through everything at the end.

Tentative (and living) checklist of stuff to add

• Dispatch fit folder functions
• Dispacth glr folder functions (underway)
• Dispatch loss-penalty folder functions (underway)
• Dispatch mlj folder functions
• tests

[adienes]

fit(::Type{T}, glr::GLR, X::AbstractMatrix{<:Real},

why introduce an argument rather than using the type of X?

[MartinuzziFrancesco]

yes there are a lot of redundancies at the moment, I started this top down while I was digging into the code instead of bottom up. I'll be fixing a lot of these in the next push