Add tasks for all the new languages

Task/Executable-library/Nim/executable-library-1.nim

@@ -0,0 +1,20 @@
+proc hailstone*(n): auto =
+  result = @[n]
+  var n = n
+  while n > 1:
+    if (n and 1) == 1:
+      n = 3 * n + 1
+    else:
+      n = n div 2
+    result.add n
+
+when isMainModule:
+  let h = hailstone 27
+  assert h.len == 112 and h[0..3] == @[27,82,41,124] and h[h.high-3..h.high] == @[8,4,2,1]
+  var m, mi = 0
+  for i in 1 .. <100_000:
+    let n = hailstone(i).len
+    if n > m:
+      m = n
+      mi = i
+  echo "Maximum length ", m, " was found for hailstone(", mi, ") for numbers <100,000"

Task/Executable-library/Nim/executable-library-2.nim

@@ -0,0 +1,10 @@
+import hailstone, tables
+
+var t = initCountTable[int]()
+
+for i in 1 .. <100_000:
+  t.inc(hailstone(i).len)
+
+let (val, cnt) = t.largest()
+echo "The length of hailstone sequence that is most common for"
+echo "hailstone(n) where 1<=n<100000, is ", val, ". It occurs ", cnt, " times."