Add datetime in logs.
Support multiple records.
Add user-agent header for providers.
Cleaning.
Use a json array for the 'names' config option.
Revert "Add user-agent header for providers."

This reverts commit 2032e47f32d83961e1630082c47bdf8c0a546329.

Conflicts:
	gandi_dyndns.py
Clean providers.json.
Do not update the zone if errors encountered.
Warn about compatibility break for config parameter 'name'.
Merge pull request #1 from foudfou/master

Add support for multiple records (thanks @foudfou!)