Adds FuelPHP 2.x component installer

Waiting for @WanWizard (project lead of FuelPHP) to confirm this is good to go.

@WanWizard: I removed the feature that trimmed fuelphp- prefix and -component suffix from package names since this one lets you to define custom package name.

Syntax:
``` json
"extra": {
    "installer-name": "component-name"
 },
```

Are you satisfied with it? Should the feature mentioned above go back?