Add tasks for all the new languages

Task/Exponentiation-operator/Lingo/exponentiation-operator.lingo

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+-- As for built-in power() function:
+-- base can be either integer or float; returns float.
+on pow (base, exp)
+  if exp=0 then return 1.0
+  else if exp<0 then
+    exp = -exp
+    base = 1.0/base
+  end if
+  res = float(base)
+  repeat with i = 2 to exp
+    res = res*base
+  end repeat
+  return res
+end