End-to-end tests now require testproxy v0.0.4, which supports the new
Reconnect command for the Pass filtering rule.
Split mode with the -n option also supports filtering rules, so the
Divert rule can enable the divert mode even with the -n option. This is
because the purpose of the -n option is to convert sslproxy into an
sslsplit, and we want to support filtering rules in sslsplit-like
sslproxy too.
The -n command line option enables split mode for all proxyspecs,
effectively making sslproxy behave like sslsplit.
Divert option can be set/unset globally and per-proxyspec.
Add e2e tests for split mode, and update make file for tests
accordingly.
Update documentation accordingly.
Improve code reuse, remove duplicate functions.
This change deserves a release of its own, hence v0.8.4.
