[SyliusWebBundle] Frontend Editing for CMS Page & Block with CMF

Hi,

Another PR to add CMF CreateBundle Integration.
![cmf-create](https://cloud.githubusercontent.com/assets/1230954/3381621/fe059746-fc23-11e3-84fc-792ba1d972db.jpg)

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | 
| License       | MIT
| Doc PR        | 

This works with Pages and Blocks (SonataBlock native) ;)
Editing is permit only to ROLE_SYLIUS_ADMIN, so you should connect to see the bundle in action.
Editor not showing on h# tag, seems to be normal process of createjs lib.
It's a good think because h# tag are designed in css file.

Waiting comments.