Move batch files to 'script' subdirectory

script/build-win.bat

@@ -2,7 +2,9 @@
 set start=%time%
 @echo on
 
-call clean-win.bat
+SET scriptdir=%~dp0
+
+call %scriptdir%\clean-win.bat
 
 echo "*** BUILDING MILKDROP ***"
 MSBuild.exe ../milkdrop2-musikcube/milkdrop2-musikcube.sln /m /nologo /verbosity:minimal /p:Configuration=Release /p:Platform=Win32
@@ -34,4 +36,4 @@ if %hours% lss 0 set /a hours = 24%hours%
 if 1%ms% lss 100 set ms=0%ms%
 set /a totalsecs = %hours%*3600 + %mins%*60 + %secs%
 @echo on
-echo Build time: %hours%:%mins%:%secs%.%ms% (%totalsecs%.%ms%s total)
+echo Build time: %hours%:%mins%:%secs%.%ms% (%totalsecs%.%ms%s total)