move all vlib modules to vlib/

vlib/os/os_win.v

@@ -0,0 +1,38 @@
+// 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 os
+
+pub fn ls(path string) []string {
+	mut res := []string
+	return res
+}
+
+pub fn getwd() string {
+	mut buffer := malloc(512)
+	
+	buffer = C._getcwd(0, 0)
+	// A NULL return value indicates an error
+	if isnil(buffer) {
+		return ''
+	}
+	return string(buffer)
+}
+
+const (
+	FILE_ATTRIBUTE_DIRECTORY = 16
+)
+
+fn is_dir(path string) bool {
+	val := int(C.GetFileAttributes(path.cstr()))
+	return val &FILE_ATTRIBUTE_DIRECTORY > 0
+}
+
+fn chdir(path string) {
+	C._chdir(path.cstr())
+}
+
+fn log(s string) {
+}
+