fix for locators service not defined 

This is a partial fix for issue https://github.com/stephpy/TimelineBundle/issues/125
- [ ] Use the config to load the locators and drop support for the tags
- [ ] Consider keeping support for tags

If you want to be 100% BC and support tags too, we could find all the tagged services, and find all the configservices. 

Pseudo code
````
foreach (configged services as service) { //get service ids}
foreach (tagged services as service) { // get service ids }

foreach (unique service ids between the two) { //do the call }
````