*List::SomeUtils* provides some trivial but commonly needed functionality
on lists which is not going to go into the List::Util manpage.

All of the below functions are implementable in only a couple of lines of
Perl code. Using the functions from this module however should give
slightly better performance as everything is implemented in C. The
pure-Perl implementation of these functions only serves as a fallback in
case the C portions of this module couldn't be compiled on this machine.