Initial draft of coroutines library.

src/test/res/coroutines.lua

@@ -0,0 +1,18 @@
+function foo (a)
+	print("foo", a)
+    return coroutine.yield(2*a)
+end
+     
+co = coroutine.create(function (a,b)
+	print("co-body", a, b)
+	local r = foo(a+1)
+	print("co-body", r)
+	local r, s = coroutine.yield(a+b, a-b)
+	print("co-body", r, s)
+	return b, "end"
+end)
+            
+print("main", coroutine.resume(co, 1, 10))
+print("main", coroutine.resume(co, "r"))
+print("main", coroutine.resume(co, "x", "y"))
+print("main", coroutine.resume(co, "x", "y"))