Fix belongsToMany with deeper associations not loading.

When deep associations are loaded from junction tables, they are loaded
as a hasMany. This means we need to accomodate for this structure as
well.

This solution doesn't make me happy but it was the smallest change
I could make. Other approaches I took caused other things to break.

src/ORM/Association/BelongsToMany.php

@@ -468,7 +468,14 @@ protected function _buildResultMap($fetchQuery, $options)
                     $property
                 ));
             }
-            $result[$this->_junctionProperty] = $result[$property];
+            $junctionData = $result[$property];
+
+            // Account for incorrectly nested data from hasMany
+            // bindings when junction tables have additional associations loaded
+            if (isset($result[$property][0])) {
+                $junctionData = $result[$property][0];
+            }
+            $result[$this->_junctionProperty] = $junctionData;
             unset($result[$property]);
 
             if ($hydrated) {
@@ -1282,7 +1289,12 @@ protected function _buildQuery($options)
             ->where($this->junctionConditions())
             ->select($query->aliasFields((array)$assoc->foreignKey(), $name));
 
-        $assoc->attachTo($query);
+        // If this hasMany attaches any other containments, then the junction
+        // table is queried twice. Ideally the EagerLoader could resolve the duplication,
+        // and merge the resulting eagerloadable instances.
+        //
+        // We have to define aliasPath, so any nested contains will work.
+        $assoc->attachTo($query, ['aliasPath' => $assoc->alias()]);
 
         return $query;
     }