Improve map unit scale dialog title and add descriptive

Author: manisandro

src/ui/qgsmapunitscaledialog.ui

@@ -11,28 +11,31 @@
    </rect>
   </property>
   <property name="windowTitle">
-   <string>Adjust map unit scales</string>
+   <string>Adjust scaling range</string>
   </property>
   <property name="windowIcon">
    <iconset resource="../../images/images.qrc">
     <normaloff>:/images/themes/default/mActionOptions.png</normaloff>:/images/themes/default/mActionOptions.png</iconset>
   </property>
   <layout class="QGridLayout" name="gridLayout">
-   <item row="0" column="0">
+   <item row="1" column="0">
     <widget class="QCheckBox" name="mCheckBoxMaxScale">
      <property name="text">
       <string>Maximum scale:</string>
      </property>
     </widget>
    </item>
-   <item row="1" column="0">
+   <item row="2" column="0">
     <widget class="QCheckBox" name="mCheckBoxMinScale">
      <property name="text">
       <string>Minimum scale:</string>
      </property>
     </widget>
    </item>
-   <item row="3" column="0" colspan="2">
+   <item row="1" column="1" colspan="2">
+    <widget class="QgsScaleComboBox" name="mComboBoxMaxScale"/>
+   </item>
+   <item row="4" column="0" colspan="2">
     <widget class="QDialogButtonBox" name="mButtonBox">
      <property name="orientation">
       <enum>Qt::Horizontal</enum>
@@ -42,12 +45,19 @@
      </property>
     </widget>
    </item>
-   <item row="0" column="1" colspan="2">
-    <widget class="QgsScaleComboBox" name="mComboBoxMaxScale"/>
-   </item>
-   <item row="1" column="1" colspan="2">
+   <item row="2" column="1" colspan="2">
     <widget class="QgsScaleComboBox" name="mComboBoxMinScale"/>
    </item>
+   <item row="0" column="0" colspan="3">
+    <widget class="QLabel" name="label">
+     <property name="text">
+      <string>Scale only within the following map unit scale range:</string>
+     </property>
+     <property name="wordWrap">
+      <bool>true</bool>
+     </property>
+    </widget>
+   </item>
   </layout>
  </widget>
  <customwidgets>
@@ -95,4 +105,3 @@
   </connection>
  </connections>
 </ui>
-