#### Summary

It looks like latest version includes `buffer.js` on the browser bundle even if not actually used.
This makes axios bundle size **3 times bigger**, adding 22kB to the minified size (0.16.0 is 11.9 KB while 0.16.1 is 33.9kB).

#### Context

- axios version: v0.16.1

lib/adapters/http.js
port: parsedProxyUrl.port
        };
        if (parsedProxyUrl.auth) {
          var proxyUrlAuth = parsedProxyUrl.auth.split(':');
          proxy.auth = {
            username: proxyUrlAuth[0],
            password: proxyUrlAuth[1]
          };
        }
      }
    }
    if (proxy) {
      options.hostname = proxy.host;
      options.host = proxy.host;
      options.headers.host = parsed.hostname + (parsed.port ? ':' + parsed.port : '');
      options.port = proxy.port;
      options.path = protocol + '//' + parsed.hostname + (parsed.port ? ':' + parsed.port : '') + options.path;
      
      if (proxy.auth) {
        var base64 = new Buffer(proxy.auth.username + ':' + proxy.auth.password, 'utf8').toString('base64');
        options.headers['Proxy-Authorization'] = 'Basic ' + base64;
      }
    }
    var transport;
    if (config.maxRedirects === 0) {
      transport = isHttps ? https : http;
    } else {
      if (config.maxRedirects) {
        options.maxRedirects = config.maxRedirects;
      }