Show locktime and according blockheights

[pvig0q1s]

It would be a nice addition to show transaction level timelocks (nLockTime, nSequence) on the confirmation screen.

@stepan: I'd like to use this issue for a personal (but public) message for you. I'm quite sure a lot of people told you this: This project is fantastic. Thank U (and all collaborators as well). I wish U all the best!