Remove tools/fract.hxx from document.hxx.

If a forward declaration does the job, use that.  Adding a new header
in document.hxx is a very expensive operation since almost everyone in sc
includes document.hxx.

Change-Id: I2d78440d65da7207ceb16cb28a7404249eba066a

sc/inc/document.hxx

@@ -37,7 +37,6 @@
 #include "compressedarray.hxx"
 #include "calcmacros.hxx"
 #include "calcconfig.hxx"
-#include <tools/fract.hxx>
 #include <tools/gen.hxx>
 #include <svl/zforlist.hxx>
 
@@ -84,6 +83,7 @@ struct ReorderParam;
 
 }
 
+class Fraction;
 class SvxFontItem;
 
 class KeyEvent;

sc/source/core/data/patattr.cxx

@@ -48,6 +48,7 @@
 #include <svl/zforlist.hxx>
 #include <vcl/outdev.hxx>
 #include <vcl/svapp.hxx>
+#include <tools/fract.hxx>
 
 #include "patattr.hxx"
 #include "docpool.hxx"