Implement the UI level change part of msiexec.

diff --git a/include/msi.h b/include/msi.h
index dee3c0e..82c46f7 100644
--- a/include/msi.h
+++ b/include/msi.h
@@ -48,7 +48,11 @@
     INSTALLUILEVEL_NONE = 2,
     INSTALLUILEVEL_BASIC = 3,
     INSTALLUILEVEL_REDUCED = 4,
-    INSTALLUILEVEL_FULL = 5
+    INSTALLUILEVEL_FULL = 5,
+    INSTALLUILEVEL_HIDECANCEL = 0x20,
+    INSTALLUILEVEL_PROGRESSONLY = 0x40,
+    INSTALLUILEVEL_ENDDIALOG = 0x80,
+    INSTALLUILEVEL_SOURCERESONLY = 0x100
 } INSTALLUILEVEL;
 
 typedef enum tagINSTALLLEVEL
@@ -231,6 +235,7 @@
  */
 UINT WINAPI MsiCloseHandle(MSIHANDLE);
 UINT WINAPI MsiCloseAllHandles();
+INSTALLUILEVEL WINAPI MsiSetInternalUI(INSTALLUILEVEL, HWND*);
 
 #ifdef __cplusplus
 }