Prepare 2.5.1 release

CHANGELOG

-mkdocs-material-2.6.0 (2017-xx-xx)
+mkdocs-material-2.5.1 (2017-01-20)
 
-  * Added permalink to main headline
-  * Added English as a fallback for missing translations
+  * Fixed permalink for main headline
+  * Improved missing translation handling with English as a fallback
   * Improved accessibility with skip-to-content link
 
 mkdocs-material-2.5.0 (2017-01-13)

docs/release-notes.md

@@ -12,7 +12,7 @@ To determine the currently installed version, use the following command:
 
 ``` sh
 pip show mkdocs-material | grep -E ^Version
-# Version 2.5.0
+# Version 2.5.1
 ```
 
 ### Material 1.x to 2.x
@@ -38,6 +38,12 @@ pip show mkdocs-material | grep -E ^Version
 
 ## Changelog
 
+### 2.5.1 <small>_ January 20, 2018</small>
+
+* Fixed permalink for main headline
+* Improved missing translation handling with English as a fallback
+* Improved accessibility with skip-to-content link
+
 ### 2.5.0 <small>_ January 13, 2018</small>
 
 * Added support for right-to-left languages