Add tasks for all the new languages

Task/Fibonacci-sequence/Lingo/fibonacci-sequence-1.lingo

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+on fib (n)
+  if n<2 then return n
+  return fib(n-1)+fib(n-2)
+end

Task/Fibonacci-sequence/Lingo/fibonacci-sequence-2.lingo

@@ -0,0 +1,11 @@
+on fib (n)
+  if n<2 then return n
+  fibPrev = 0
+  fib = 1
+  repeat with i = 2 to n
+    tmp = fib
+    fib = fib + fibPrev
+    fibPrev = tmp
+  end repeat
+  return fib
+end

Task/Fibonacci-sequence/Lingo/fibonacci-sequence-3.lingo

@@ -0,0 +1,6 @@
+on fib (n)
+  sqrt5 = sqrt(5.0)
+  p = (1+sqrt5)/2
+  q = 1 - p
+  return integer((power(p,n)-power(q,n))/sqrt5)
+end