doc: tls: clarify server cipher list

* Make it clear that ECDHE-RSA-AES128-SHA256 and AES128-GCM-SHA256 are
  TLS v1.2 ciphers.

* Note that RC4 is under suspicion.
doc: tls: note that SSLv2 is disabled by default

As of commit 39aa894, SSLv2 support is disabled by default.  Update
the documentation to reflect that.
lib: introduce `.setMaxSendFragment(size)`

fix #6889
test: ignore tests when built without OpenSSL CLI

fix #6880
test: refactor to use common testcfg
test: move debugger repl into own section
debug client: connect after child is ready

We now wait to connect to the debuggee until we know that
its error stream has data, to ensure that the output message
"connecting..... ok" appears after "Debugger listening on port xyz"

I also increased the test timeout to let the more complex
tests finish in time on Windows

This change fixes the following unit tests on Windows:
 test-debugger-repl.js test-debugger-repl-term.js test-debugger-repl-utf8.js
 test-debugger-repl-restart.js
test: debug-signal-cluster increase timeouts

The test needs a little more time to run so that it passes for all
builds (eg: Windows, debug)
addons: build and test examples

fix #6910
node: `EmitExit` should not call `exit()`

Before this commit `RunAtExit` and `env->Dispose()` were never reached,
because `EmitExit` was always colling `exit`.
doc: fix
addons: share testcfg.py