Add ImperialCivil Units Schema

- units for civil engineering - ft, ft2, ft3, mph,
  and angles as degrees/minutes/seconds

src/Gui/DlgSettingsUnits.ui

@@ -6,7 +6,7 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>380</width>
+    <width>484</width>
     <height>388</height>
    </rect>
   </property>
@@ -100,6 +100,11 @@
             <string>Metric small parts &amp; CNC(mm, mm/min)</string>
            </property>
           </item>
+          <item>
+           <property name="text">
+            <string>Imperial Civil (ft/ft^2/ft^3)</string>
+           </property>
+          </item>
          </widget>
         </item>
        </layout>