SunrisePlugin does not take DST into account

[gabryelreyes]

• Currently configured to Latitude 48.39 and Longitude 9.98
• Plugin shows Sunrise at 5:05 and Sunset at 16:02.
• Real sunrise and sunset offset one hour later than shown by the plugin.
• Probably addCurrentTimezoneValues method does not take the DST into account.

How to reproduce:

• Add SunrisePlugin to one of the slots in http://pixelix/display.html
• Set Latitude and Logitude of current location in http://pixelix/plugins/SunrisePlugin.html
• Compare times shown by the plugin with the time shown by a Google Search of "sunrise" or "sunset" accordingly
• Times should have a difference of around one hour (as are calculated by different services)

[BlueAndi]

see #29 - bugfix is available, but its still not merged to the Arduino lib as it looks like