Perl 6 'is export(...)' trait as a Perl 5 attribute

 Export::Attrs is a fork of Perl6::Export::Attrs created to restore
 compatibility with Perl6::Export::Attrs version 0.0.3.
 .
 Implements a Perl 5 native version of what the Perl 6 symbol export mechanism
 will look like (with some unavoidable restrictions).