DRAFT: stdlib: add Comparing and Sorting to replace Int-returning compareTo/sortAs methods

[soc]

@dinfuehr Do you have an idea to turn -1/0/1 into Less/Equal/Greater / Before/Same/After without introducing additional branches?

(I guess one idea would be to return 0/1/2 instead and translate them into the enum variant tags?)

What do you think?

[dinfuehr]

Enums without arguments should already be simple integers, so both enums should already use 0/1/2 as values. (We might want to change the encoding to -1/0/1 but I guess that's initially not too important)

[soc]

Will pick this up again at a later date.