Merge pull request #405 from duxet/fix

Remove unused imports from Model

src/Jenssegers/Mongodb/Model.php

 <?php namespace Jenssegers\Mongodb;
 
-use Illuminate\Database\Eloquent\Collection;
 use Jenssegers\Mongodb\DatabaseManager as Resolver;
 use Jenssegers\Mongodb\Eloquent\Builder;
-use Jenssegers\Mongodb\Query\Builder as QueryBuilder;
 use Illuminate\Database\Eloquent\Relations\Relation;
 use Jenssegers\Mongodb\Relations\EmbedsOneOrMany;
 use Jenssegers\Mongodb\Relations\EmbedsMany;