Improve toolbars on small screens

- normalized toolbars in message viewer, contact viewer and contact
  editor;
- lower width of sidenav on medium screens;
- reworked display of message headers

UI/Templates/SchedulerUI/UIxAppointmentViewTemplate.wox

@@ -5,7 +5,7 @@
     xmlns:const="http://www.skyrix.com/od/constant"
     xmlns:label="OGo:label">
   <md-dialog flex="40" flex-md="60" flex-sm="100">
-      <md-toolbar class="md-padding" ng-class="editor.component.getClassName('bg')">
+      <md-toolbar ng-class="editor.component.getClassName('bg')">
         <div class="md-toolbar-tools">
           <md-icon class="material-icons sg-icon-toolbar-bg">event</md-icon>
           <div class="sg-md-title md-flex">

UI/Templates/SchedulerUI/UIxTaskEditorTemplate.wox

@@ -7,7 +7,7 @@
   <md-dialog flex="60" flex-sm="100">
     <form name="eventForm" ng-submit="editor.save(eventForm)">
       <md-toolbar ng-class="editor.component.getClassName('bg')">
-        <div class="md-toolbar-tools sg-padded">
+        <div class="md-toolbar-tools">
           <!-- summary -->
           <md-icon ng-if="editor.component.classification == 'confidential'">visibility_off</md-icon>
           <md-icon ng-if="editor.component.classification == 'private'">vpn_key</md-icon>

UI/Templates/SchedulerUI/UIxTaskViewTemplate.wox

@@ -5,7 +5,7 @@
     xmlns:const="http://www.skyrix.com/od/constant"
     xmlns:label="OGo:label">
   <md-dialog flex="40" flex-md="60" flex-sm="100">
-    <md-toolbar class="md-padding" ng-class="editor.component.getClassName('bg')">
+    <md-toolbar ng-class="editor.component.getClassName('bg')">
       <div class="md-toolbar-tools">
         <md-icon class="material-icons sg-icon-toolbar-bg">assignment_turned_in</md-icon>
         <div class="sg-md-title md-flex">