Update apple-touch-icon-precomposed.png

iPhone 6 Plus now uses a `180×180px` apple touch icon.

Ref: http://www.mobilexweb.com/blog/safari-ios8-iphone6-web-developers-designers

Author: alrra

dist/apple-touch-icon-precomposed.png

@@ -598,6 +598,7 @@ The main sizes of the icons on iOS are:
 * `120×120px` – iPhone 4+ (with Retina Display) on iOS ≥ 7
 * `144×144px` – iPad 3+ (with Retina Display)
 * `152×152px` – iPad 3+ (with Retina Display)
+* `180×180px` – iPhone 6 Plus
 
 For non-Retina iPhone, iPod Touch, and Android 2.1+ devices you can use the
 example from above or replace the `apple-touch-icon-precomposed.png` within

dist/doc/extend.md

@@ -598,6 +598,7 @@ The main sizes of the icons on iOS are:
 * `120×120px` – iPhone 4+ (with Retina Display) on iOS ≥ 7
 * `144×144px` – iPad 3+ (with Retina Display)
 * `152×152px` – iPad 3+ (with Retina Display)
+* `180×180px` – iPhone 6 Plus
 
 For non-Retina iPhone, iPod Touch, and Android 2.1+ devices you can use the
 example from above or replace the `apple-touch-icon-precomposed.png` within