Add some common exception classes.
Add a Queue class.
Add a short doc comment for min() and max().
Use memmove() and memset() from the std C library instead of rewriting.
Move some functions from the `global` module to a new `util` module.

It still doesn’t seem clean having the `util` module like it is, but
better than having the functions in `global`.
Use std.math instead of tango.math.Math.
Remove dependency on tango.io.model.IFile.