Improve encapsulation. SCH_LINE has no business knowing about drags.

eeschema/sch_line.cpp

@@ -156,13 +156,28 @@ int SCH_LINE::GetLineStyleInternalId( const wxString& aStyleName )
 
 void SCH_LINE::Move( const wxPoint& aOffset )
 {
-    if( (m_Flags & STARTPOINT) == 0 && aOffset != wxPoint( 0, 0 ) )
+    if( aOffset != wxPoint( 0, 0 ) )
+    {
+        m_start += aOffset;
+        m_end += aOffset;
+        SetModified();
+    }
+}
+
+
+void SCH_LINE::MoveStart( const wxPoint& aOffset )
+{
+    if( aOffset != wxPoint( 0, 0 ) )
     {
         m_start += aOffset;
         SetModified();
     }
+}
+
 
-    if( (m_Flags & ENDPOINT) == 0 && aOffset != wxPoint( 0, 0 ) )
+void SCH_LINE::MoveEnd( const wxPoint& aOffset )
+{
+    if( aOffset != wxPoint( 0, 0 ) )
     {
         m_end += aOffset;
         SetModified();

eeschema/sch_line.h

@@ -122,6 +122,8 @@ public:
     int GetPenSize() const override;
 
     void Move( const wxPoint& aMoveVector ) override;
+    void MoveStart( const wxPoint& aMoveVector );
+    void MoveEnd( const wxPoint& aMoveVector );
 
     void MirrorX( int aXaxis_position ) override;