Add codereview.settings.

Add codereview.settings.

This is for us to use codereview.appspot.com for code reviews.

Instructions to use codereview.appspot.com:

1. Get depot_tools and add PATH to the directory
http://dev.chromium.org/developers/how-tos/depottools

2. In your local IBus git repository,

% git checkout master
% git checkout -b somefix
make changes
% git cl upload
do code reviews at codereview.appspot.com
once it's done, run "git cl push" if you can commit.
otherwise, ask committers to commit on behalf.

Review URL: http://codereview.appspot.com/2166043