Allow filtering of objects for select element
Allow filtering of objects for select element

just add 
```
filter_by => array('age' => 20)
```

to the options when defining the form field
Bilge/DoctrineModule,gencer/DoctrineModule,malukenho/DoctrineModule,netiul/DoctrineModule,marek1989/DoctrineModule,UFOMelkor/DoctrineModule,malukenho/DoctrineModule,alirezarahmani/DoctrineModule,inbaz/DoctrineModule,doctrine/DoctrineModule,Bilge/DoctrineModule,vasildakov/DoctrineModule,mpalourdio/DoctrineModule,UFOMelkor/DoctrineModule