Added new future module with a closure macro.

tests/closure/tclosuremacro.nim

@@ -0,0 +1,43 @@
+discard """
+  output: '''10
+10
+10
+3
+3
+noReturn
+'''
+"""
+
+import future
+
+when false:
+  proc twoParams(x: (int, int) -> int): int =
+    result = x(5, 5)
+
+  proc oneParam(x: int -> int): int =
+    x(5)
+
+  proc noParams(x: () -> int): int =
+    result = x()
+
+  proc noReturn(x: () -> void) =
+    x()
+
+  proc doWithOneAndTwo(f: (int, int) -> int): int =
+    f(1,2)
+
+  echo twoParams(proc (a, b): auto = a + b)
+  echo twoParams((x, y) => x + y)
+
+  echo oneParam(x => x+5) 
+
+  echo noParams(() => 3)
+
+  echo doWithOneAndTwo((x, y) => x + y)
+
+  noReturn(() -> void => echo("noReturn"))
+
+proc pass2(f: (int, int) -> int): (int) -> int =
+  (x: int) -> int => f(2, x)
+
+#echo pass2((x, y) => x + y)