Add support for multiple tile map entities
Improve basic render system performances
Expose subpackage to the api package

Now we can simply do:

```python
from pyludic import api
api.core.init()
api.stats.get_framerate()
```

instead of

```python
from pyludic.api import core
from pyludic.api import stats
core.init()
stats.get_framerate()
```