Give (non-type) global constants upper case names

[SouthEndMusic]

My apologies for the many PR's, but this is a very simple one. All I did was give (non-type) global constants upper case names. This helps with readability of the code for people who are not familiar with all the variable names.

[visr]

Float is a type though right? const Float = Float64 it is a type alias. I don't see an issue for it, but I think it should be removed altogether, so we just use Float64 instead. The original idea was to start using it to support running in single precision but this is only half (so not) supported. And if we would start supporting it we'd use type parameters rather than a type alias.

[SouthEndMusic]

Ah right Float is a type. For that one I thought it was nice to rename it because there are also instances of Float64 in the code base so if you search for FLOAT you don't get false positives

And if we would start supporting it we'd use type parameters rather than a type alias

Then I think indeed it can be removed, but that might require some refactoring of type parameters

[visr]

Yeah I made a separate issue, #535. I'm fine with renaming it as well in this PR.

[vers-w]

Then I think indeed it can be removed, but that might require some refactoring of type parameters

Yes, I agree this can be removed, for me it's fine to do this as part of this PR.