XML files (backupStarted.xml backupEnded.xml and scheduler.xml) for backup surveillance are written to the server
Added client identification to the XML which will be uploaded to the server
backupID has is now from datatype long, using QTemporaryFile for local scheduler.xml, backupStarted.xml and backupEnded.xml
About dialog redesigned

* Removed images from copyright and development company
* Remove 'Developed by' since that information is of no interest to a
  user, interested developers have that information in the AUTHORS file
* Shortened 'Copyright by' line
* Use Sepiola logo if no reseller is set
* Display a link to the Github bug tracker in the vanilla version
  (branded versions will get a reseller-specific support-address)
Removed the static const bool Settings::IS_RESELLER because it is only used for the about dialog. Using #ifdef IS_RESLLER instead
Rewrite getTimezoneOffset() to be a local function