Add ImperialCivil Units Schema

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

src/Base/Quantity.h

@@ -256,6 +256,8 @@ public:
     static Quantity Degree;
     static Quantity Radian;
     static Quantity Gon;
+    static Quantity AngMinute;
+    static Quantity AngSecond;
     //@}