[SETUPLIB][USETUP] Move some code to the SetupLib.

- filesup.c's functions ConcatPaths(), Does[Path|File]Exist(), NtPathToDiskPartComponents(), OpenAndMapFile(), UnMapFile();
- Move the inicache library to setuplib as it'll be used for the 1st stage GUI setup too (indeed, there is no good INI file API
  under Win32; the Win32 profile "API" is just good enough to manipulate the win16 ini files, and are here anyways for backward
  compatibility purposes only);
- Move the OS detector too.
- Remove the duplicated ConcatPaths() code in arcname.c.

svn path=/branches/setup_improvements/; revision=74634
svn path=/branches/setup_improvements/; revision=74638

base/setup/usetup/usetup.h

@@ -60,7 +60,6 @@
 /* Internal Headers */
 #include "consup.h"
 #include "inffile.h"
-#include "inicache.h"
 #include "progress.h"
 #include "infros.h"
 #include "filequeue.h"
@@ -70,7 +69,6 @@
 #include "cabinet.h"
 #include "filesup.h"
 #include "genlist.h"
-#include "osdetect.h"
 #include "mui.h"
 
 extern HANDLE ProcessHeap;