base58: add paranoid return value checks
add NetworkIDString() to chainparams

- returns the BIP70 network string
- use that new function in the core and GUI code and remove unused code
  and functions
bitcoin-cli, rpcclient: prefer EXIT_FAILURE cstdlib constant

A more complex construction via abs() yields the same end result.

Rebased-From: 34ff109
Rebased-By: Wladimir J. van der Laan <laanwj@gmail.com>
Remove cli functionality from bitcoind

As it says on the tin. It was deprecated in version 0.9, and
at some point it should be removed.

Removes the dependency of bitcoind on libbitcoin-cli.a. Move
some functions that used to be shared but are now only used in
bitcoin-cli.cpp to that file.

After this change, an error is printed (and exit code 1 is returned)
when the user tries to send RPC commands using bitcoind.
Merge pull request #4232

b750cf1 Remove cli functionality from bitcoind (Wladimir J. van der Laan)
Merge pull request #4337

88df548 base58: add paranoid return value checks (Jeff Garzik)
Merge pull request #4326

f5ae6c9 add NetworkIDString() to chainparams (Philip Kaufmann)
Remove `using namespace std` from header file

It's considered bad form to import things into the global namespace in a
header. Put it in the cpp files where it is needed instead.
Merge pull request #4349

09eb201 Remove `using namespace std` from header file (Wladimir J. van der Laan)
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