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.

diff --git a/dlls/msacm32/filter.c b/dlls/msacm32/filter.c
index 45dc02c..b0fddca 100644
--- a/dlls/msacm32/filter.c
+++ b/dlls/msacm32/filter.c
@@ -4,7 +4,7 @@
  *      Copyright 1998  Patrik Stridvall
  */
 
-#include "windows.h"
+#include "winbase.h"
 #include "winerror.h"
 #include "wintypes.h"
 #include "debug.h"