Add tasks for all the new languages

Task/Non-continuous-subsequences/Nim/non-continuous-subsequences.nim

@@ -0,0 +1,19 @@
+import sequtils
+
+proc ncsub[T](se: seq[T], s = 0): seq[seq[T]] =
+  result = @[]
+  if se.len > 0:
+    let
+      x = se[0..0]
+      xs = se[1 .. -1]
+      p2 = s mod 2
+      p1 = (s + 1) mod 2
+    for ys in ncsub(xs, s + p1):
+      result.add(x & ys)
+    result.add(ncsub(xs, s + p2))
+  elif s >= 3:
+    result.add(@[])
+
+echo "ncsub(", toSeq 1.. 3, ") = ", ncsub(toSeq 1..3)
+echo "ncsub(", toSeq 1.. 4, ") = ", ncsub(toSeq 1..4)
+echo "ncsub(", toSeq 1.. 5, ") = ", ncsub(toSeq 1..5)