converted smbd to use NTSTATUS by default

major changes include:

- added NSTATUS type
- added automatic mapping between dos and nt error codes
- changed all ERROR() calls to ERROR_DOS() and many to ERROR_NT()
  these calls auto-translate to the client error code system
- got rid of the cached error code and the writebmpx code

We eventually will need to also:
- get rid of BOOL, so we don't lose error info
- replace all ERROR_DOS() calls with ERROR_NT() calls

but that is too much for one night

source/include/smb.h

@@ -205,9 +205,10 @@ typedef struct nttime_info
 {
   uint32 low;
   uint32 high;
-
 } NTTIME;
 
+typedef uint32 NTSTATUS;
+
 /* Allowable account control bits */
 #define ACB_DISABLED   0x0001  /* 1 = User account disabled */
 #define ACB_HOMDIRREQ  0x0002  /* 1 = Home directory required */
@@ -370,7 +371,6 @@ typedef struct files_struct
 	SMB_OFF_T size;
 	mode_t mode;
 	uint16 vuid;
-	write_bmpx_struct *wbmpx_ptr;
 	write_cache *wcp;
 	struct timeval open_time;
 	int share_mode;