Prepare for intermediate version 1.6.3

https://github.com/FreshRSS/FreshRSS/milestone/22

CHANGELOG.md

@@ -1,6 +1,6 @@
 # Changelog
 
-## 2017-xx-xx FreshRSS 1.7.0-dev
+## 2017-03-xx FreshRSS 1.6.3-dev
 
 * Features
 	* Share with Ⓚnown [#1420](https://github.com/FreshRSS/FreshRSS/pull/1420)

constants.php

@@ -1,5 +1,5 @@
 <?php
-define('FRESHRSS_VERSION', '1.7.0-dev');
+define('FRESHRSS_VERSION', '1.6.3-dev');
 define('FRESHRSS_WEBSITE', 'http://freshrss.org');
 define('FRESHRSS_WIKI', 'http://doc.freshrss.org');