Time estimation in downloading blocks is not real

[kaminskyelina]

Bug title
Time estimation in downloading blocks is not real

Bug description
Time estimation in downloading blocks is not accurate and not real

Option A: fix the time estimation and make it correct.
Option B: Change the text “Downloading block X out of Y”, where X – currently downloaded block, Y – total blockchain height. Needs to be tested for large block numbers (max is 69,904,800) so that it fits.
Option C: combine A + B
Option B is much preferable – easy to implement and test. Correct time estimation in this case will be very hard to do since network conditions are hard to predict.

*Reported by Alexander Zaidelson

[gingervik]

duplicate of #206