Add tasks for all the new languages

Task/Arithmetic-Rational/Lingo/arithmetic-rational-1.lingo

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+-- parent script "Frac"
+property num
+property denom
+
+----------------------------------------
+-- @constructor
+-- @param {integer} numerator
+-- @param {integer} [denominator=1]
+----------------------------------------
+on new (me, numerator, denominator)
+  if voidP(denominator) then denominator = 1
+  if denominator=0 then return VOID -- rule out division by zero
+  g = me._gcd(numerator, denominator)
+  if g<>0 then
+    numerator = numerator/g
+    denominator = denominator/g
+  else
+    numerator = 0
+    denominator = 1
+  end if
+  if denominator<0 then
+    numerator = -numerator
+    denominator = -denominator
+  end if
+  me.num = numerator
+  me.denom = denominator
+  return me
+end
+
+----------------------------------------
+-- Returns string representation "<num>/<denom>"
+-- @return {string}
+----------------------------------------
+on toString (me)
+  return me.num&"/"&me.denom
+end
+
+----------------------------------------
+--
+----------------------------------------
+on _gcd (me, a, b)
+  if a = 0 then return b
+  if b = 0 then return a
+  if a > b then return me._gcd(b, a mod b)
+  return me._gcd(a, b mod a)
+end