Refactor ecobenefits views to avoid decorators

Similar to the treemap app, eco benefits now follows a schema
similar to:

```python
def benefits_for_tree(instance, tree_id):
    return ...

benefits_for_tree_view = json_api_call(
    instance_req(strip_req(benefits_for_tree)))
```
Add numpy for the eco.py library
Merge pull request #79 from ahinz/topic/eco-views

Refactor ecobenefits views to avoid decorators