Remove mentions of firebug, which has not existed for many years (#364)

Author: niloc132

src/main/markdown/doc/latest/DevGuideA11y.md

@@ -375,8 +375,7 @@ Make sure to test that a new widget is accessible! There are three basic steps i
 
 *   **DOM**
 
-      Since ARIA attributes are being added directly to the DOM, an easy way to check that the attributes are in the right location is to use a DOM inspector like
-      [Firebug](http://getfirebug.com/) or the [Chrome developer tools](https://developers.google.com/chrome-developer-tools/).
+      Since ARIA attributes are being added directly to the DOM, an easy way to check that the attributes are in the right location is to use your browser's dev tools's DOM inspector.
 
 *   **Events**
 

src/main/markdown/doc/latest/DevGuideLogging.md

@@ -140,8 +140,7 @@ Most of the default Handlers are very straightforward
 
 *   `SystemLogHandler` - Logs to stdout.  These messages can only be seen in Development Mode — look for them in the DevMode window
 *   `DevelopmentModeLogHandler` - Logs by calling method GWT.log. These messages can only be seen in Development mode — look for them in the DevMode window
-*   `ConsoleLogHandler` - Logs to the javascript console, which is used by Firebug Lite (for IE), Safari and Chrome(?)
-*   `FirebugLogHandler` - Logs to Firebug
+*   `ConsoleLogHandler` - Logs to each browser's own built-in Dev Tools console
 *   `PopupLogHandler` - Logs to the popup which appears in the upper left hand corner
 *   `SimpleRemoteLogHandler` - Discussed below, in the Remote Logging section
 
@@ -226,7 +225,6 @@ HTMLFormatter
   TextFormatter
   SystemLogHandler
   ConsoleLogHandler
-  FirebugLogHandler
   DevelopmentModeLogHandler
   HasWidgetsLogHandler (and LoggingPopup to use with it)
 ```

src/main/markdown/doc/latest/DevGuideTestingRemoteTesting.md

@@ -125,8 +125,6 @@ Plugin. On our test systems, we use the following settings:
     *   Type 'about:config' in the browser bar 
     *   Find browser.sessionstore.resume_from_crash and set it to false
     *   Find browser.sessionstore.enabled and set it to false (if it exists)
-*   Install [Firebug](http://getfirebug.com/) (useful for debugging)
-*   Install the [GWT Developer Plugin](/missing-plugin/)
 *   Whitelist the hosts that will launch the development mode code server. Since Selenium copies the profile for each test, you must do this now.  If you do not, you will have to allow the remote connection for every test!
     *   Restart Firefox 
     *   Tools -> Addons

src/main/markdown/doc/latest/FAQ_UI.md

@@ -44,7 +44,7 @@ And here is how the screen ends up:
 What went wrong? We set the Dock Panel to fill up 100% of the space, and then each button to the left or right of the screen. At this point, it can be helpful to probe and see
 what the boundaries of your widgets are, because they may not be where you think.
 
-The first technique is to use a DOM inspection tool, such as [Firebug](http://www.getfirebug.com) for the [Firefox](http://www.mozilla.com) browser. As you hover over elements in the DOM they will highlight in the browser window.
+The first technique is to use your browser's dev tools. As you hover over elements in the DOM they will highlight in the browser window.
 
 Another technique you can use is to modify your GWT code to turn on borders on your panels (or other widgets.)
 

src/main/markdown/overview.md

@@ -35,7 +35,7 @@ You aren't limited to pre-canned widgets either. Anything you can do with the br
 
 You can debug AJAX applications in your favorite IDE just like you would a desktop application, and in your favorite browser just like you would if you were coding JavaScript. The GWT developer plugin spans the gap between Java bytecode in the  debugger and the browser's JavaScript.
 
-Thanks to the GWT developer plugin, there's no compiling of code to JavaScript to view it in the browser. You can use the same edit-refresh-view cycle you're used to with JavaScript, while at the same time inspect variables, set breakpoints, and utilize all the other debugger tools available to you with Java. And because GWT's development mode is now in the browser itself, you can use tools like Firebug and Inspector as you code in Java.
+Thanks to the GWT developer plugin, there's no compiling of code to JavaScript to view it in the browser. You can use the same edit-refresh-view cycle you're used to with JavaScript, while at the same time inspect variables, set breakpoints, and utilize all the other debugger tools available to you with Java. And because GWT's development mode is now in the browser itself, you can use browser dev tools as you code in Java.
 
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