Add tasks for all the new languages

Task/Fibonacci-sequence/Nim/fibonacci-sequence-1.nim

@@ -0,0 +1,5 @@
+proc Fibonacci(n: int): int64 =
+  var fn = float64(n)
+  var p: float64 = (1.0 + sqrt(5.0)) / 2.0
+  var q: float64 = 1.0 / p
+  return int64((pow(p, fn) + pow(q, fn)) / sqrt(5.0))

Task/Fibonacci-sequence/Nim/fibonacci-sequence-2.nim

@@ -0,0 +1,10 @@
+proc Fibonacci(n: int): int =
+  var
+    first = 0
+    second = 1
+
+  for i in 0 .. <n:
+    swap first, second
+    second += first
+
+  result = first

Task/Fibonacci-sequence/Nim/fibonacci-sequence-3.nim

@@ -0,0 +1,5 @@
+proc Fibonacci(n: int): int64 =
+  if n <= 2:
+    result = 1
+  else:
+    result = Fibonacci(n - 1) + Fibonacci(n - 2)

Task/Fibonacci-sequence/Nim/fibonacci-sequence-4.nim

@@ -0,0 +1,7 @@
+proc Fibonacci(n: int, current: int64, next: int64): int64 =
+  if n == 0:
+    result = current
+  else:
+    result = Fibonacci(n - 1, next, current + next)
+proc Fibonacci(n: int): int64 =
+  result = Fibonacci(n, 0, 1)

Task/Fibonacci-sequence/Nim/fibonacci-sequence-5.nim

@@ -0,0 +1,11 @@
+iterator fib: int {.closure.} =
+  var a = 0
+  var b = 1
+  while true:
+    yield a
+    swap a, b
+    b = a + b
+
+var f = fib
+for i in 0.. <10:
+  echo f()