i18n: updating translations

Also remove some strings that should not be translated or
that were not displayed

Change-Id: Ia973e6ea06f349b1b3db20b4664d29c7510c4bbe
diff --git a/callwidget.ui b/callwidget.ui
index ee54fe8..0843637 100644
--- a/callwidget.ui
+++ b/callwidget.ui
@@ -17,7 +17,7 @@
    </sizepolicy>
   </property>
   <property name="windowTitle">
-   <string>Form</string>
+   <string/>
   </property>
   <layout class="QGridLayout" name="gridLayout">
    <property name="leftMargin">