String consistency.

modules/gui/qt4/ui/sprefs_audio.ui

@@ -290,7 +290,7 @@
    <item>
     <widget class="QGroupBox" name="lastFMBox" >
      <property name="title" >
-      <string>_("Last.fm")</string>
+      <string>_("last.fm")</string>
      </property>
      <layout class="QGridLayout" >
       <item row="0" column="0" colspan="2" >

modules/gui/qt4/ui/sprefs_input.ui

@@ -17,7 +17,7 @@
    <item>
     <widget class="QGroupBox" name="groupBox" >
      <property name="title" >
-      <string>_("Disk Devices")</string>
+      <string>_("Disc Devices")</string>
      </property>
      <layout class="QGridLayout" >
       <item row="0" column="0" >

modules/gui/qt4/ui/sprefs_subtitles.ui

@@ -53,7 +53,7 @@
       <item row="0" column="0" >
        <widget class="QLabel" name="label" >
         <property name="text" >
-         <string>_("Preferred Subtitle language")</string>
+         <string>_("Preferred subtitles language")</string>
         </property>
         <property name="buddy" >
          <cstring>preferredLanguage</cstring>