code: function resolveValue(model, property) {
    var unwrappedContext = typeof model[property] === 'function' ? model[property]() : model[property];
    return Postmate.Promise.resolve(unwrappedContext);
  }
docs: Takes a model, and searches for a value by the property
  @param  {Object} model     The dictionary to search against
  @param  {String} property  A path within a dictionary (i.e. 'window.location.href')
  @param  {Object} data      Additional information from the get request that is
  passed to functions in the child model
  @return {Promise}