require() webpack-cli/webpack-command's bin module
require() webpack-cli/webpack-command's bin module

Rather than require()-ing the "main" module in webpack-cli/
webpack-command, require() the "bin" module.

This avoids the issue described in
https://github.com/webpack-contrib/webpack-command/pull/30
where installing packages in this order results in no output from
./node_modules/.bin/webpack:

    $ npm install webpack-command
    $ npm install webpack
    $ ./node_modules/.bin/webpack
    # exit 0 with no output

webpack/webpack,NekR/webpack,EliteScientist/webpack,NekR/webpack,EliteScientist/webpack,webpack/webpack,SimenB/webpack,webpack/webpack,SimenB/webpack,SimenB/webpack,SimenB/webpack,webpack/webpack