Add options object for the analytics.load call

[mzogheib]

There doesn't appear to be a way to provide options for the load call. See here.

Similar to page options, how about something like this?

var snippet = require('@segment/snippet');

var contents = snippet.max({
  host: 'cdn.segment.com',
  apiKey: '03fwkuu3',
  page: {
    category: 'Docs',
    name: 'Integrations',
    properties: {
      foo: 'bar'
    }
  },
  load: {
    integrations: {
      All: false,
      AdRoll: true
    }
  }
});

[mzogheib]

Resolved in #66