[sr-dev] method mask for xlog

[Juha Heinanen]

i'm thinking to add method mask to xlog module.  when xlog() is called,
nothing happens if method of request or reply is included in the mask.
the mask could be set at run rime via an rpc command and would default
to 0.

using the mask, it would be easy, for example, to prevent logging of
OPTIONS requests without a need to add if statements to the script.

any comments?

-- juha