Extracted paintDays method

Signed-off-by: Rafał Malinowski <rafal.malinowski@corp.bluecherry.net>
Small refactoring in EventTimelineWidget::paintDays method

Signed-off-by: Rafał Malinowski <rafal.malinowski@corp.bluecherry.net>
Implement EventTimelineWidget::timeXOffset method

Signed-off-by: Rafał Malinowski <rafal.malinowski@corp.bluecherry.net>
Fixed EventData::serverEndDate method

Signed-off-by: Rafał Malinowski <rafal.malinowski@corp.bluecherry.net>
Fixed values of time span

Signed-off-by: Rafał Malinowski <rafal.malinowski@corp.bluecherry.net>
Only allow UTC times in DateTimeRange

Signed-off-by: Rafał Malinowski <rafal.malinowski@corp.bluecherry.net>
Fix problem with UTC offset in timeline widget

Signed-off-by: Rafał Malinowski <rafal.malinowski@corp.bluecherry.net>
Fixed timeCellRect method

Signed-off-by: Rafał Malinowski <rafal.malinowski@corp.bluecherry.net>