Allow for disabling individual languages, closes #66

ftplugin/xs.vim

@@ -1,3 +1,5 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'perl') == -1
+  
 " Vim filetype plugin file
 " Language:      XS (Perl extension interface language)
 " Maintainer:    vim-perl <vim-perl@googlegroups.com>
@@ -12,3 +14,5 @@ endif
 
 " Just use the C plugin for now.
 runtime! ftplugin/c.vim ftplugin/c_*.vim ftplugin/c/*.vim
+
+endif