Update Pimple for use Pimple2 refs #65 #63

Update Pimple without use alias and directly the good tags, because Composer cannot choices between Pimple 2.1.0 and 2.1.1 for Silex/api

```
 Problem 1
    - silex/api 2.0.x-dev requires pimple/pimple ~2.1 -> satisfiable by pimple/pimple[v2.1.0, v2.1.1].
    - Can only install one of: pimple/pimple[v3.0.0, v2.1.0].
    - Can only install one of: pimple/pimple[v3.0.0, v2.1.1].
    - cilex/cilex dev-develop requires pimple/pimple 3.0.0 as 2.1.0 -> satisfiable by pimple/pimple[v3.0.0].
    - cilex/cilex dev-develop requires silex/api 2.0.x-dev -> satisfiable by silex/api[2.0.x-dev].
    - Installation request for cilex/cilex dev-develop -> satisfiable by cilex/cilex[dev-develop].
```