[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.
add comment to HelpMessage() to ensure alphabetical ordering

- also rename hmm to mode, to be consistent between .h and .cpp
Merge pull request #4357

1020f59 add comment to HelpMessage() to ensure alphabetical ordering (Philip Kaufmann)
Get rid of Params().RPCisTestNet()
Add "chain" to getmininginfo, improve help in getblockchaininfo
Merge pull request #4333

f6984e8 Add "chain" to getmininginfo, improve help in getblockchaininfo (jtimon)
b82b7ec Get rid of Params().RPCisTestNet() (jtimon)
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)
rpc: Ignore and log errors during cancel

Cancelling the RPC acceptors can sometimes result in an error about
a bad file descriptor.

As this is the shutdown sequence we need to continue nevertheless,
ignore these errors, log a warning and proceed.

Fixes #4352.
rpc: Add acceptors only when listening succeeded