Remove notes about Google Chrome Frame from docs

Currently we don't use Google Chrome Frame anymore as support for
it will end at the end of the year.
This commit removes references to Chrome Frame within the
documentation. It is related to 2cf1ef7.

Reference h5bp#1433.

Author: drublic

doc/css.md

@@ -31,7 +31,7 @@ These include:
 * Basic typography settings to provide improved text readability by default.
 * Protection against unwanted `text-shadow` during text highlighting.
 * Tweaks to default image alignment, fieldsets, and textareas.
-* A pretty Chrome Frame prompt.
+* A pretty prompt to update your browser if you are on an outdated browser.
 
 You are free to modify or add to these base styles as your project requires.
 

doc/extend.md

@@ -144,7 +144,7 @@ element, which will prompt them to switch to Desktop Mode.
 Here's what it looks like alongside H5BP's default X-UA-Compatible values:
 
 ```html
-<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1,requiresActiveX=true">
+<meta http-equiv="X-UA-Compatible" content="IE=edge,requiresActiveX=true">
 ```
 
 You can find more information in [Microsoft's IEBlog post about prompting for

doc/html.md

@@ -47,10 +47,6 @@ vectors](http://code.google.com/p/doctype-mirror/wiki/ArticleUtf7).
 
 The meta tag for compatibility mode [needs to be before all elements except
 title and meta](http://h5bp.com/f "Defining Document Compatibility - MSDN").
-And that same meta tag can only be invoked for Google Chrome Frame if it is
-within the [first 1024
-bytes](http://code.google.com/p/chromium/issues/detail?id=23003).
-
 
 ## X-UA-Compatible
 
@@ -125,11 +121,11 @@ The central part of the boilerplate template is pretty much empty. This is
 intentional, in order to make the boilerplate suitable for both web page and
 web app development.
 
-### Google Chrome Frame
+### Browserhappy Promt
 
-The main content area of the boilerplate includes a prompt to install Chrome
-Frame (which no longer requires administrative rights) for users of IE 6. If
-you intended to support IE 6, then you should remove the snippet of code.
+The main content area of the boilerplate includes a prompt to install an up to
+date browser for users of IE 6. If you intended to support IE 6, then you should
+remove the snippet of code.
 
 ### Google CDN for jQuery