Add tasks for all the new languages

Task/Function-frequency/Sidef/function-frequency.sidef

@@ -0,0 +1,19 @@
+var program = <<'EOT'
+func foo { }
+func bar { }
+
+foo(); foo(); foo()
+bar(); bar();
+EOT
+
+var parser = Parser.new                     # initialize a new parser
+parser.parse_script( code => program )      # parse the code
+
+var data = Perl.to_sidef(parser{:vars}{:main}).flatten
+
+data.sort_by { |v| -v{:count} }.first(10).each { |entry|
+    if (entry{:type} == :func) {
+        say ("Function `#{entry{:name}}` (declared at line",
+             " #{entry{:line}}) is used #{entry{:count}} times")
+    }
+}