Establish an ISA relationship with base classes at compile time
Description
base module allows you to both load one or more modules, while setting up inheritance from
those modules at the same time.
When base tries to require a module, it will not die if it cannot find the module's file,
but will die on any other error. After all this, should your base class be empty, containing
no symbols, base will die. This is useful for inheriting from classes in the same file as
yourself but where the filename does not match the base module name.
base will also initialize the fields if one of the base classes has it. Multiple inheritance
of fields is NOT supported, if two or more base classes each have inheritable fields the 'base'
pragma will croak. See fields for a description of this feature.
