windows: force removal without confirmation for clean scripts

windows/clean.bat

@@ -1,2 +1,2 @@
 Rem manually performs "make clean"
-del *.aux *.d *.toc *.out *.log *.nav *.snm *.sbx *.sxd
+FOR %%A IN (*.aux *.d *.toc *.out *.log *.nav *.snm *.sbx *.sxd) DO DEL %%A

windows/cleanall.bat

@@ -1,3 +1,4 @@
+Rem remove pdf files
+FOR %%A IN (*.pdf) DO DEL %%A
 Rem manually performs "make cleanall"
 windows\\clean.bat
-del *.pdf