move all vlib modules to vlib/

vlib/rand/rand.v

@@ -0,0 +1,18 @@
+// Copyright (c) 2019 Alexander Medvednikov. All rights reserved.
+// Use of this source code is governed by an MIT license
+// that can be found in the LICENSE file.
+
+module rand
+
+import time
+
+pub fn seed() {
+	C.srand(time.now().uni)
+}
+
+pub fn next(max int) int {
+	return C.rand() % max
+}
+
+fn C.rand() int 
+