This fixes NTLM authentication with Outlook2003.

Remove some no longer relevant fixmes.

Fix a typo in rpcrt4_conn_open_pipe where the initial setting of dwFlags 
was done inside the switch statement instead of at the indented place of 
at the start of the block (thanks to Jan Zerebecki for noticing this bug).

Implement the SHAddFromPropSheetExtArray, SHCreatePropSheetExtArray,
SHReplaceFromPropSheetExtArray and SHDestroyPropSheetExtArray functions
that are used to extend/replace property sheets by shell extensions.