r464: a big improvement to the API for writing server-side RPC

r464: a big improvement to the API for writing server-side RPC
servers. Previously the server pipe code needed to return the RPC
level status (nearly always "OK") and separately set the function call
return using r->out.result. All the programmers writing servers
(metze, jelmer and me) were often getting this wrong, by doing things
like "return NT_STATUS_NO_MEMORY" which was really quite meaningless
as there is no code like that at the dcerpc level.

I have now modified pidl to generate the necessary boilerplate so that
just returning the status you want from the function will work. So for
a NTSTATUS function you return NT_STATUS_XXX and from a WERROR
function you return WERR_XXX. If you really want to generate a DCERPC
level fault rather than just a return value in your function then you
should use the DCESRV_FAULT() macro which will correctly generate a
fault for you.

As a side effect, this also adds automatic type checking of all of our
server side rpc functions, which was impossible with the old API. When
I changed the API I found and fixed quite a few functions with the
wrong type information, so this is definately useful.

I have also changed the server side template generation to generate a
DCERPC "operation range error" by default when you have not yet filled
in a server side function. This allows us to correctly implement
functions in any order in our rpc pipe servers and give the client the
right information about the fault.