New std.uni: ready for more beating

[tn]

Hi. Just a couple stupid questions:

* What is the relation between std.uni and std.utf? Why is two 
modules needed? Seems confusing to me. Shouldn't these be 
combined? If not, then please explain the the distinction in the 
beginning of the module documentation.

* Shouldn't the module be renamed to std.unicode? We do not have 
std.arr, std.alg or std.cont either. To me, it is not at all 
obvious what std.uni contains based on the module name.