doc: examples: show-upgradeable: removed obsolete Makefile
lib: download: progress: support setting download size before starting download
lib: download: progresses: updateHook: don't display not started downloads
lib: download: manager: worker: set download sizes immediately after scheduling
lib: download: progress: fixed undercalculating done size/percent when 'ui-size' messages were sent

This was a regressioin from '058bb784'.
debian: changelog: 2.6.0: last download manager changes improve total percent accuracy
lib: download: progress: setTotalEstimatedSize: removed, not needed anymore