Feature/client api

[the-overengineer]

Adds support for the Client API configuration getting, enabling, disabling, and editing. Adds unit tests for the new resources and methods, and integration tests to describe the four desired scenarios.

Example:

var application; // Fetched beforehand

application.getWebConfig(function(err, webConfig) {
  webConfig.status = 'ENABLED'; // 'enabled' also works, but will be set to uppercase when saving
  webConfig.save(function(err, webConfigEnabled) {
    if (err) {
      throw err;
    }

    console.log(webConfigEnabled.status === 'ENABLED'); // true
    webConfigEnabled.me.expand.tenant = true;

    webConfigEnabled.save(function(err, webConfigSaved) {
      if (err) {
        throw err;
      }

      console.log(webConfigSaved.me.expand.tenant); // true
    });
  });
});

Fixes #579

[coveralls]

Coverage increased (+0.07%) to 89.557% when pulling 11cc87a on feature/client-api into bcc4597 on master.

[coveralls]

Coverage decreased (-1.3%) to 88.227% when pulling 104d113 on feature/client-api into bcc4597 on master.

[coveralls]

Coverage decreased (-0.03%) to 88.125% when pulling 421cf1a on feature/client-api into 9ba3642 on master.