Optimized include/*.h: (recursively) include all headers needed by
this .h file, but only those. Necessary fixes to a lot of .c files,
started optimizing "windows.h" away from some of them. Moved
GetCurrentTask prototype to wine/winbase16.h.

include/toolhelp.h

diff --git a/include/toolhelp.h b/include/toolhelp.h
index 8b422a9..1286d3d 100644
--- a/include/toolhelp.h
+++ b/include/toolhelp.h
@@ -1,7 +1,7 @@
 #ifndef __WINE_TOOLHELP_H
 #define __WINE_TOOLHELP_H
 
-#include "windows.h"
+#include "windef.h"
 #include "tlhelp32.h"
 
 #define MAX_DATA	11