LimeSDR: GUI cosmetic changea

plugins/samplesource/limesdrinput/limesdrinputgui.ui

@@ -6,7 +6,7 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>374</width>
+    <width>360</width>
     <height>290</height>
    </rect>
   </property>
@@ -18,7 +18,7 @@
   </property>
   <property name="minimumSize">
    <size>
-    <width>350</width>
+    <width>360</width>
     <height>290</height>
    </size>
   </property>
@@ -272,7 +272,7 @@
         <cursorShape>PointingHandCursor</cursorShape>
        </property>
        <property name="toolTip">
-        <string>NCO frequency (Hz)</string>
+        <string>NCO frequency shift in Hz</string>
        </property>
       </widget>
      </item>
@@ -585,6 +585,19 @@
        </property>
       </widget>
      </item>
+     <item>
+      <spacer name="horizontalSpacer">
+       <property name="orientation">
+        <enum>Qt::Horizontal</enum>
+       </property>
+       <property name="sizeHint" stdset="0">
+        <size>
+         <width>40</width>
+         <height>20</height>
+        </size>
+       </property>
+      </spacer>
+     </item>
      <item>
       <widget class="ButtonSwitch" name="lpFIREnable">
        <property name="toolTip">