Resource identifier / Add configuration for the identifier prefix.

To provide more flexibility on the type of resource identifier added by the suggestion mechanism a new configuration option is added to the administration and is used when a resource identifier is computed.


## Configuration

![image](https://cloud.githubusercontent.com/assets/1701393/4926115/b553c0ec-6530-11e4-8258-30c82aed1ebb.png)


## Suggestion 

![image](https://cloud.githubusercontent.com/assets/1701393/4926124/c14787a8-6530-11e4-8dc7-5a933b736e09.png)

## Resource identifier

![image](https://cloud.githubusercontent.com/assets/1701393/4926120/bb9b6d06-6530-11e4-8b09-737962833311.png)