[Qt] rename In:/Out: to Received/Sent in traffic tab

- collides with In:/Out: used for displaying number of
  connections when translating
Add `-stopafterblockimport` option

Stop after importing blocks. This can be useful for development
and trouble shooting.
sanity: autoconf check for sys/select.h
sanity: add libc/stdlib sanity checks

These are meant to test our back-compat stubs, but they are enabled for all
builds for the sake of consistency.
sanity: hook up sanity checks
Added encryptwallet call to bitrpc.py

This was the only call requiring password input which was still missing. Much useful to avoid leaving a plain text passphrase in the shell log.
Merge pull request #4346

1569353 Add `-stopafterblockimport` option (Wladimir J. van der Laan)
Merge pull request #4354

7ad720d Added encryptwallet call to bitrpc.py (dllud)
Merge pull request #4339

92a6220 sanity: hook up sanity checks (Cory Fields)
679240d sanity: add libc/stdlib sanity checks (Cory Fields)
11404af sanity: autoconf check for sys/select.h (Cory Fields)
Merge pull request #4334

6763018 [Qt] rename In:/Out: to Received/Sent in traffic tab (Philip Kaufmann)
rework closesocket()

- make closesocket() the pure Win32 API call on Win32
- make closesocket() emulate the Win32 behaviour on all other OSes
extend and cleanup use of closesocket()

- add missing closesocket() calls for BindListenPort()
- always call closesocket() before printing any text (ensure consistent
  usage in the code)

misc small changes in net:
- remove unused CNode::Cleanup()
- add missing vhListenSocket.clear() to ~CNetCleanup()

changes in ConnectSocketDirectly() unrelated to closesocket():
- replace 3 following calls to WSAGetLastError() by storing result into
  nErr and use this in an if-clause
- convert an if() to an else if(), which removes an unneded check if the
  first case is true