Blocktime format rounding

[jacogr]

Displays 13:57:47 as 15:37 as opposed to 15:38 (Reference now goes from blockTime -> current as opposed to the other way around)

May improve display for https://github.com/ethcore/parity/issues/3888

[coveralls]

Changes Unknown when pulling 6efaec8 on jg-fix-status-blocktime into ** on master**.

[derhuerst]

Not sure, I understand this correctly. Cannot confirm that this fixes rounds 15:37:40 to 15:38.

[jacogr]

Watch it with debugging info across 50 odd blocks pre-and-post logging the blocks numbers, blocktimes and moment display values with both versions - moment has differences between the rounding depending on what you go from and what you go to with .calendar(...). (current -> blocktime is different from blocktime -> current)

Pre this change it rounds up so you end up with displayed timestamps that has not happened yet.

[derhuerst]

Pre this change it rounds up so you end up with displayed timestamps that has not happened yet.

Thanks for the clarification. Can confirm this PR fixes the issue.