PyOWM config as a dict

[csparpa]

New interface for injecting config into the main PyOWM entry point.

Requirements

The config dict can be provided either:

• as an external file
• as a Python dict

The config file are JSON based

Each OWM API (weather API, pollution API, etc..) has its own configuration
section in the global config dict

TODOs

• place a default config file into the rooot PyOWM folder. This will collect
  info from modules: pyowm.constants, pyowm.webapi25.configuration25,
  pyowm.webapi25.owm25.OWM25 and from the entry point of package pyowm
• implement config dict reading/writing from/to file
• take the actual pyowm.webapi25.configuration25.weather_code_registry data structure out
  from configuration and put it into a specific module. Also city_id_registry shall not
  be instantiated here but by the OWM class
• refactor the PyOWM factory system, changing the main library object from OWM25 to OWM (more generic)
• create a documentation page about config
• have setup.py take the info it needs from the default config file

This is the logic format for the config dict:

GLOBAL
  - default language
  - default API subscription type
CONNECTION
  - use ssl (boolean)
  - verify SSL certs (boolean)
  - default connection timeout
CITY ID REGISTRY
  - pattern of city ID files (es. 'cityids/%03d-%03d.txt.gz')

Example of config load

Something like:

from pyowm import OWM, load_config_from
config_dict = load_config_from('/path/to/config.py')
owm = OWM('your-api-key', config_dict)