Clasifiying .test into subdirectories per functionality

Addresses issue #552 

Taking into account the extra text added by directory names to the output, some lines gets cut, eg.:

```
097/220: 000_ngsi10_convenience/convenience_ngsi10_individual_context_entity_attributes_d 01 seconds
098/220: 000_ngsi10_convenience/convenience_ngsi10_individual_context_entity_attributes_d 01 seconds
099/220: 000_ngsi10_convenience/convenience_ngsi10_individual_context_entity_attributes_g 01 seconds
100/220: 000_ngsi10_convenience/convenience_ngsi10_individual_context_entity_attributes_g 02 seconds
101/220: 000_ngsi10_convenience/convenience_ngsi10_individual_context_entity_attributes_p 01 seconds
102/220: 000_ngsi10_convenience/convenience_ngsi10_individual_context_entity_attributes_p 01 seconds
103/220: 000_ngsi10_convenience/convenience_ngsi10_individual_context_entity_attributes_p 01 seconds
104/220: 000_ngsi10_convenience/convenience_ngsi10_individual_context_entity_attributes_p 02 seconds
```

Maybe we should add +20 characters to the tabulation in order to fix this. However, not sure where to touch in the test harness engine to do that. @kzangeli , could you adjust this branch with that fix before merging?