First implementation of the initial configuration handler
First implementation of the initial configuration handler

Looks after files named ".pelix.conf" in standard configuration folders and "merge" their content.
A configuration file can define environment variables, Python path folders, a list of bundles to install and start (list of names) and a list of components to instantiate (a list of objects with "name", "factory", "properties" entries).

Should fix #62

Sample file:
```json
{
    "properties": {
        "framework.uid": "toto",
        "other": [1, 2, 3]
    },
    "bundles": [
        "pelix.http.basic"
    ],
    "components": [
        {
            "factory": "pelix.http.service.basic.factory",
            "name": "httpd",
            "properties": {
                "pelix.http.port": 8088
            }
        }
    ]
}
```

tcalmant/ipopo