code: function or(schema, ...args) {
  	if (!objtools.isPlainObject(schema)) {
  		args.unshift(schema);
  		schema = {};
  	}
  	schema.type = 'or';
  	schema.alternatives = args;
  	return schema;
  }
docs: Generates a subschema that's an OR between two or more other schemas (ie, any of the
  listed components can match).  Use it like this:
  
  ```js
  createSchema({
  foo: or({ required: true }, String, Number)
  })
  ```
  
  @method or
  @param {Object} schema - Schema params or empty object.  This can be left out if the first
  arg isn't an object.
  @param {Mixed} args... - Subschemas that are alternatives.
  @return {Object} The `or` type subschema.