add OpenSSL RAND_cleanup() on OpenSSL shutdown

- to securely erase the memory used by the PNRG
- also rework 2 comments in OpenSSL init
rpc: Prevent easy memory exhaustion attack

Allocate memory for POST message data only as bytes come in, instead of
all at once at the beginning.

Fixes #4343.
[Qt] remove dup includes in bitcoingui
[Qt] seed OpenSSL PNRG with Windows event data

- see https://bitcointalk.org/index.php?topic=113496.msg1228193#msg1228193
  for the initial suggestion for this
- also ensure consistent debug.log message format
[Qt] Replace status bar unit icon with actual images
Remove unused variable
Fix CChain::GetLocator
Add CChain::GetLocator() unit test
Rename SendMoneyToDestination to SendMoney.

Get rid of SendMoney and replace it by the functionality of
SendMoneyToDestination.  This cleans up the code, since only
SendMoneyToDestination was actually used (SendMoney internally from this
routine).
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)
Use GetBlockTime() more
Merge pull request #4463

e832ab7 Rename SendMoneyToDestination to SendMoney. (Daniel Kraft)
Merge pull request #4470

f4b00be Add CChain::GetLocator() unit test (Pieter Wuille)
3c85d2e Fix CChain::GetLocator (Pieter Wuille)
Merge pull request #4446

209377a Use GetBlockTime() more (jtimon)
Merge pull request #4373

2ec5a3d rpc: Prevent easy memory exhaustion attack (Wladimir J. van der Laan)
Merge pull request #4399

674c070 [Qt] seed OpenSSL PNRG with Windows event data (Philip Kaufmann)