initial Flask app and controller

get some functional Flask RESTful code in:

To start:
`python app.py`

testing RESTful endpoints isn't as straightforward as unit tests. For now, to test locally:
```
curl -X GET http://127.0.0.1:5000/platforms/abc123
curl -X PUT http://127.0.0.1:5000/platforms/abc123?name=ABC123
curl -X DELETE http://127.0.0.1:5000/platforms/abc123
curl -X GET http://127.0.0.1:5000/platforms
curl -X GET http://127.0.0.1:5000/platforms?type=FILTER_BY_TYPE
curl -X POST --data "key1=value1&key2=value2" http://127.0.0.1:5000/platforms
```

CAUTION (requirements.txt): pip freeze places numpy after netCDF4 which will fail