Fix setting output/device for Xine and VLC backend

- Fixed setting output and device on Xine and VLC backend
- Fixed track slider for Xine, VLC and Phonon
- Improved backend settings to better support multiple backends
- Added group by samplerate and bitdepth in collection
- Fixed crash on exit when existing instance of the application is already runnung caused by NVIDIA driver
- Changed Q_OS_MAC to Q_OS_MACOS

src/collection/groupbydialog.ui

@@ -7,7 +7,7 @@
     <x>0</x>
     <y>0</y>
     <width>354</width>
-    <height>236</height>
+    <height>246</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -19,7 +19,7 @@
   </property>
   <layout class="QVBoxLayout" name="verticalLayout">
    <item>
-    <widget class="QLabel" name="label_4">
+    <widget class="QLabel" name="label">
      <property name="text">
       <string>You can change the way the songs in the collection are organised.</string>
      </property>
@@ -35,14 +35,14 @@
      </property>
      <layout class="QFormLayout" name="formLayout">
       <item row="0" column="0">
-       <widget class="QLabel" name="label">
+       <widget class="QLabel" name="label_first">
         <property name="text">
          <string>First level</string>
         </property>
        </widget>
       </item>
       <item row="0" column="1">
-       <widget class="QComboBox" name="first">
+       <widget class="QComboBox" name="combobox_first">
         <item>
          <property name="text">
           <string>None</string>
@@ -103,6 +103,16 @@
           <string>Bitrate</string>
          </property>
         </item>
+        <item>
+         <property name="text">
+          <string>Sample rate</string>
+         </property>
+        </item>
+        <item>
+         <property name="text">
+          <string>Bit depth</string>
+         </property>
+        </item>
         <item>
          <property name="text">
           <string>Disc</string>
@@ -121,14 +131,14 @@
        </widget>
       </item>
       <item row="1" column="0">
-       <widget class="QLabel" name="label_2">
+       <widget class="QLabel" name="label_second">
         <property name="text">
          <string>Second level</string>
         </property>
        </widget>
       </item>
       <item row="1" column="1">
-       <widget class="QComboBox" name="second">
+       <widget class="QComboBox" name="combobox_second">
         <item>
          <property name="text">
           <string>None</string>
@@ -189,6 +199,16 @@
           <string>Bitrate</string>
          </property>
         </item>
+        <item>
+         <property name="text">
+          <string>Sample rate</string>
+         </property>
+        </item>
+        <item>
+         <property name="text">
+          <string>Bit depth</string>
+         </property>
+        </item>
         <item>
          <property name="text">
           <string>Disc</string>
@@ -207,14 +227,14 @@
        </widget>
       </item>
       <item row="2" column="0">
-       <widget class="QLabel" name="label_3">
+       <widget class="QLabel" name="label_third">
         <property name="text">
          <string>Third level</string>
         </property>
        </widget>
       </item>
       <item row="2" column="1">
-       <widget class="QComboBox" name="third">
+       <widget class="QComboBox" name="combobox_third">
         <item>
          <property name="text">
           <string>None</string>
@@ -275,6 +295,16 @@
           <string>Bitrate</string>
          </property>
         </item>
+        <item>
+         <property name="text">
+          <string>Sample rate</string>
+         </property>
+        </item>
+        <item>
+         <property name="text">
+          <string>Bit depth</string>
+         </property>
+        </item>
         <item>
          <property name="text">
           <string>Disc</string>
@@ -309,7 +339,7 @@
     </spacer>
    </item>
    <item>
-    <widget class="QDialogButtonBox" name="button_box">
+    <widget class="QDialogButtonBox" name="buttonbox">
      <property name="orientation">
       <enum>Qt::Horizontal</enum>
      </property>
@@ -321,17 +351,17 @@
   </layout>
  </widget>
  <tabstops>
-  <tabstop>first</tabstop>
-  <tabstop>second</tabstop>
-  <tabstop>third</tabstop>
-  <tabstop>button_box</tabstop>
+  <tabstop>combobox_first</tabstop>
+  <tabstop>combobox_second</tabstop>
+  <tabstop>combobox_third</tabstop>
+  <tabstop>buttonbox</tabstop>
  </tabstops>
  <resources>
   <include location="../../data/data.qrc"/>
  </resources>
  <connections>
   <connection>
-   <sender>button_box</sender>
+   <sender>buttonbox</sender>
    <signal>accepted()</signal>
    <receiver>GroupByDialog</receiver>
    <slot>accept()</slot>
@@ -347,7 +377,7 @@
    </hints>
   </connection>
   <connection>
-   <sender>button_box</sender>
+   <sender>buttonbox</sender>
    <signal>rejected()</signal>
    <receiver>GroupByDialog</receiver>
    <slot>reject()</slot>