progress with futures

tests/parallel/tsysspawn.nim

@@ -0,0 +1,31 @@
+discard """
+  output: '''4
+8'''
+  cmd: "nimrod $target --threads:on $options $file"
+"""
+
+import threadpool
+
+var
+  x, y = 0
+
+proc p1 =
+  for i in 0 .. 10_000:
+    discard
+
+  atomicInc x
+
+proc p2 =
+  for i in 0 .. 10_000:
+    discard
+
+  atomicInc y, 2
+
+for i in 0.. 3:
+  spawn(p1())
+  spawn(p2())
+
+sync()
+
+echo x
+echo y