CBlockIndex()::SetNull() method to avoid code repetition
[Qt] remove dup includes in bitcoingui
Remove unused variable
Use pong receive time rather than processing time
Merge pull request #4472

9f4da19 Use pong receive time rather than processing time (Pieter Wuille)
Merge pull request #4457

834e46e CBlockIndex()::SetNull() method to avoid code repetition (jtimon)
qt: Pick translation messages only from necessary files

Utility libraries (common, util) as well as extra tools shouldn't be
parsed for translation messages, only the server and wallet part qualify
here.
Move ui_interface to bitcoin_server.a

There is no need for it in the utility libraries or tools.
Put it in init.cpp, and in the tests separately (as they can't link init).
Merge pull request #4459

73ac7ab Move ui_interface to bitcoin_server.a (Wladimir J. van der Laan)
5090303 qt: Pick translation messages only from necessary files (Wladimir J. van der Laan)
Merge pull request #4467

1f740dd Remove unused variable (R E Broadley)
Merge pull request #4462

3d0e92d [Qt] remove dup includes in bitcoingui (Philip Kaufmann)
replace ComputeMinWork with CheckMinWork
Remove redundant pblock->nNonce = 0
Move UpdateTime to pow
Move CBlockIndex::GetBlockWork() to pow::GetLengthIncrement(nBits)
Simplify and rename CheckWork to ProcessBlockFound
Encapsulate proof of work generation in pow