module providing aliases for __PACKAGE__

 CLASS is a minimalistic Perl module that simply provides aliases for the
 special literal, __PACKAGE__, which represents the current package name at
 that point during program execution. The aliases are mapped at compile-time,
 so there is no performance hit except for compilation of the module itself.
 .
 This module ensures that CLASS and $CLASS can be used anywhere in place of
 __PACKAGE__, and since $CLASS is a scalar, it has the additional benefit of
 working in strings.