peek for Fermin

### This is not a PR
Just used to interchange info.
Will be removed after fulfilling its purpose
Let's discuss `<regex to detec servicePath>`. At this point, the field in the csub document should be either:

```
...
"servicePath": "/a/b"
...
```

or 

```
...
"servicePath": "/a/b/#"
...
```

Let's consider servicePath in the updateContext has the following form:

```
Fiware-ServicePath: /a1/a2/.../aN
```

That matches with queries/subscriptions:

* /a1/a2/.../aN
* /a1/a2/.../aN/#
* /a1/a2/.../aN-1/#
* ...
* /a1/a2/#
* /a1/#
* /#

Thus, the regex to find this should be:

^/#$ | /^a1/#$ | ^/a1/a2/#$ | ... | ^/a1/a2/.../aN-1/#$ | ^/a1/a2/.../aN(/#)?$

Of course, the above is not a valid regex (e.g. no whitespace arround `|`, not sure if `/` is valid directly or should be esacped, etc.). You probably need to play a bit with tools like http://rubular.com/ to tunne the righ one it before coding. Moreover, the regex could be suboptimal (there are N+2 tokens chained with `|`, maybe they could be factorized) but by the moment I think it suffices.

Thus, the updateContext logic should tokenize the Fiware-ServicePath using "/" as separator to build the N+2 tokens needed in the servicePath query for csubs collection in addTriggeredSubscriptions().