Add perl6

Perl 6 is the next major revision of the Perl programming language.  Although the language and its implementations are still under development, most of those implementations are hosted here on GitHub, along with most of the libraries that currently exist.  For example:

  * https://github.com/perl6/nqp
  * https://github.com/perl6/doc
  * https://github.com/perl6/roast
  * https://github.com/rakudo/rakudo
  * https://github.com/sorear/niecza
  * https://github.com/jnthn/rakudo-debugger
  * https://github.com/masak/ufo
  * https://github.com/jnthn/zavolaj
  * https://github.com/masak/xml-writer
  * https://github.com/moritz/svg
  * https://github.com/moritz/Math-RungeKutta
  * https://github.com/moritz/svg-plot
  * https://github.com/moritz/Math-Model
  * https://github.com/tadzik/perl6-Term-ANSIColor
  * https://github.com/jnthn/test-mock
  * https://github.com/perlpilot/Grammar-Profiler-Simple
  * https://github.com/jnthn/grammar-debugger
  * https://github.com/moritz/json
  * https://github.com/cosimo/perl6-digest-md5
  * https://github.com/tadzik/panda
  * https://github.com/supernovus/perl6-http-status
  * https://github.com/supernovus/perl6-http-easy
  * https://github.com/tadzik/Template-Mojo
  * https://github.com/tadzik/Bailador
  * https://github.com/perl6/DBIish
  * https://github.com/colomon/uri
  * https://github.com/cosimo/perl6-lwp-simple
  * https://github.com/bbkr/jsonrpc
  * https://github.com/perl6/Pod-To-HTML
  * https://github.com/perl6/doc
  * https://github.com/moritz/Perl6-MIME-Base64
  * https://github.com/supernovus/perl6-psgi
  * https://github.com/tadzik/Shell-Command
  * https://github.com/tadzik/File-Find

Thanks,
Rob