The width for EM_SETTARGETDEVICE is used by some applications to set the
wrapping width to a certain distance in twips. This can be used even
though the target device is ignored.
The methods in ITextHost are mostly thin wrappers around functions that
take a handle to a window as their first parameter. This patch just
uses the wrapper functions provided by ITextHost instead of using the
functions that require a handle to a window that the editor might now
have (for windowless richedit controls).
