GUACAMOLE-817: Reset keyboard state on navigation and form submission.

Firefox, and perhaps other browsers, does not fire a keyup event for
keys involved in submitting a form. This results in the enter key being
stuck in a pressed state if it is used to submit Guacamole's login

Keyboard state should be reset whenever keyboard state cannot be
reliably maintained. This is already done for loss of window focus, but
should also be done for form submission (this specific case) and
navigation to a different page (generic catch-all).
diff --git a/guacamole/src/main/webapp/app/index/controllers/indexController.js b/guacamole/src/main/webapp/app/index/controllers/indexController.js
index 15e7819..ac2fec4 100644
--- a/guacamole/src/main/webapp/app/index/controllers/indexController.js
+++ b/guacamole/src/main/webapp/app/index/controllers/indexController.js
@@ -138,6 +138,12 @@
+    // Release all keys upon form submission (there may not be corresponding
+    // keyup events for key presses involved in submitting a form)
+    $document.on('submit', function formSubmitted() {
+        keyboard.reset();
+    });
      * Checks whether the clipboard data has changed, firing a new
      * "guacClipboard" event if it has.
@@ -188,6 +194,11 @@
         $scope.fatalError = error;
+    // Ensure new pages always start with clear keyboard state
+    $scope.$on('$routeChangeStart', function routeChanging() {
+        keyboard.reset();
+    });
     // Update title and CSS class upon navigation
     $scope.$on('$routeChangeSuccess', function(event, current, previous) {