New feature: Weather provider can be chosen from Yahoo! and Wunderground

Hello,

Some modifications and bug fixes added to master branch, if you have a time to review please merge them.

The API key can be got from Wunderground website: http://www.wunderground.com/weather/api/
Minor bug fixes:
- new variable in config.php can be generated without error
- if master is used then the program number is correct on the top line
- if master is used then the total time is correct on the status page