[WIP] Support multiple @find-by annotations

Still open tasks but basic support for multiple ```@find-by```. Still requiring some new unit tests and ```ElementCollection``` see #48 for more details.

Closes #13
Any reason for using `empty($annotations)` VS `$annotations`? Due typecasting empty array is converted to `false` in IFs, so just `$annotations` also work (actually before it was `!$annotations`).