Implements the maximize_window function

Specs documented here:
https://code.google.com/p/selenium/wiki/JsonWireProtocol#/session/:sessionId/window/:windowHandle/maximize

lib/Selenium/Remote/Commands.pm

@@ -69,6 +69,11 @@ has '_cmds' => (
                 'url'                => 'session/:sessionId/window/:windowHandle/position',
                 'no_content_success' => 0
             },
+            'maximizeWindow' => {
+                'method'             => 'POST',
+                'url'                => 'session/:sessionId/window/:windowHandle/maximize',
+                'no_content_success' => 1
+            },
             'setWindowSize' => {
                 'method'             => 'POST',
                 'url'                => 'session/:sessionId/window/:windowHandle/size',

lib/Selenium/Remote/Driver.pm

@@ -1587,6 +1587,30 @@ sub set_window_size {
     return $ret ? 1 : 0;
 }
 
+=head2 maximize_window
+
+ Description:
+    Maximizes the browser window
+
+ Input:
+    STRING - <optional> - window handle (default is 'current' window)
+
+ Output:
+    BOOLEAN - Success or failure
+
+ Usage:
+    $driver->maximize_window();
+
+=cut
+
+sub maximize_window {
+    my ( $self, $window ) = @_;
+    $window = ( defined $window ) ? $window : 'current';
+    my $res = { 'command' => 'maximizeWindow', 'window_handle' => $window };
+    my $ret = $self->_execute_command( $res );
+    return $ret ? 1 : 0;
+}
+
 =head2 get_all_cookies
 
  Description: