show sunrise/sunrise time and other change

Code change including
* New command `sun [location]` to show the sunrise/sunset time
* Code refactor for alfred_weather.py to avoid code copy
* Bug fix:  [https://github.com/jason0x43/jc-weather/blob/master/alfred_weather.py#L344] 
* Using blank icon for copyright information. Because now Alfred will use workflow icon as default if there is no item icon.

Also update
* README.md
* screenshot
* binary file
* version number is update.json and info.plist