Add Perl6 to languages.yml
Add sample Perl 6 files
Update samples file
Remove duplicate extensions for Perl 6
Merge branch 'pr/750' into perl_6

Conflicts:
	lib/linguist/samples.json
Removing non-Perl 6 specific extensions
Merge branch 'master' into perl_6

Conflicts:
	lib/linguist/samples.json
Merge pull request #858 from github/perl_6

Perl 6