Fixes failures in these tests on NT4.

The wireCLIPFORMAT represents the memory equivalent format of the wire
format and not the wire format itself.

Also update the tests to do the same.

Some programs alter propsheet style in the callback during creation to make
"embedded" propsheets. PSH_MODELESS controls modal/modeless operation only.

The latter was unused while the former did not seem very useful.

These functions were just being used for addition, so it was simpler to
remove the functions and modify the places it was used.

The ME_StrRelPos2 and ME_PosToVPos were just simple wrappers around
ME_StrRelPos, and ME_PosToVPos wasn't being used.

These two functions were being used for simple operations, to get the
first or last character when pre-computing flags for splitting runs.

The call to ME_GetCharBack wasn't even giving the correct result, it
would always return -1 since it is being called with nPos of 0.

This patch simplifies the code by removing the functions and getting the
characters directly from the string.

These functions were probably previously needed because of some wierd
special handling of backspace characters, but currently there is no
reason why the nLen field can't be accessed directly.

Having to functions that just access the string length field just causes
slightly more effort for someone to look at the code, because they need
to enter the function to find out what it actually is doing.

The function was just returning the second parameter.  It had some
commented out code that indicated that previously backslashes weren't
included in the length.  Native wordpad doesn't handle backspaces in a
special way, so this must have been an internal representation that
complicated finding the position of characters.