Add tasks for all the new languages

Task/Assertions/Lingo/assertions.lingo

@@ -0,0 +1,17 @@
+-- in a movie script
+on assert (ok, message)
+  if not ok then
+    if not voidP(message) then _player.alert(message)
+    abort -- exits from current call stack, i.e. also from the caller function
+  end if
+end
+
+-- anywhere in the code
+on test
+  x = 42
+  assert(x=42, "Assertion 'x=42' failed")
+  put "this shows up"
+  x = 23
+  assert(x=42, "Assertion 'x=42' failed")
+  put "this will never show up"
+end