Add tasks for all the new languages

Task/Call-a-function/Sidef/call-a-function-1.sidef

@@ -0,0 +1,10 @@
+foo();                       # without arguments
+foo(1, 2);                   # with two arguments
+foo(args...);                # with a variable number of arguments
+foo(name: 'Bar', age: 42);   # with named arguments
+
+var f = foo;                 # store the function foo inside 'f'
+var result = f();            # obtain the return value of a function
+
+var arr = [1,2,3];
+foo(arr);                    # the arguments are passed by object-reference

Task/Call-a-function/Sidef/call-a-function-2.sidef

@@ -0,0 +1,12 @@
+func curry(f, *args1) {
+    func (*args2) {
+        f(args1..., args2...);
+    }
+}
+
+func add(a, b) {
+    a + b
+}
+
+var adder = curry(add, 1);
+say adder(3);                 #=>4