Add tasks for all the new languages

Task/Entropy/Sidef/entropy.sidef

@@ -0,0 +1,10 @@
+func entropy(s) {
+  var counts = Hash.new;
+  s.each { |c| counts{c} := 0 ++ };
+  var len = s.len;
+  [0, counts.values.map {|count|
+    var freq = count/len; freq * freq.log2 }...
+  ]«-»;
+}
+ 
+say entropy("1223334444");