Add tasks for all the new languages

Task/Undefined-values/FreeBASIC/undefined-values.freebasic

@@ -0,0 +1,8 @@
+' FB 1.05.0 Win64
+
+Dim i As Integer        '' initialized to 0 by default
+Dim j As Integer = 3    '' initialized to 3
+Dim k As Integer = Any  '' left uninitialized (compiler warning but can be ignored)
+
+Print i, j, k
+Sleep

Task/Undefined-values/Lingo/undefined-values.lingo

@@ -0,0 +1,9 @@
+put var
+-- <Void>
+put var=VOID
+-- 1
+put voidP(var)
+-- 1
+var = 23
+put voidP(var)
+-- 0

Task/Undefined-values/Phix/undefined-values.phix

@@ -0,0 +1,13 @@
+object x
+
+procedure test()
+    if object(x) then
+        puts(1,"x is an object\n")
+    else
+        puts(1,"x is unassigned\n")
+    end if
+end procedure
+
+test()
+x = 1
+test()

Task/Undefined-values/Sidef/undefined-values.sidef

@@ -0,0 +1,13 @@
+var x;      # declared, but not defined
+x == nil   && say "nil value";
+defined(x) || say "undefined";
+
+# Give "x" some value
+x = 42;
+
+defined(x) && say "defined";
+
+# Change "x" back to `nil`
+x = nil;
+
+defined(x) || say "undefined";

Task/Undefined-values/jq/undefined-values-1.jq

@@ -0,0 +1 @@
+{}["key"] #=> null

Task/Undefined-values/jq/undefined-values-2.jq

@@ -0,0 +1 @@
+1/0 == null #=>false

Task/Undefined-values/jq/undefined-values-3.jq

@@ -0,0 +1 @@
+def sum: reduce .[] as $x (null; . + $x);