tests: Add a new client test

The new test tries to connect to a port where Riemann is not listening,
to test that error path as well.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
tests: Move the network_tests_enabled() function to the main file

The network_tests_enabled() function is used by check_simple too, not
only check_client, so move it to check_libriemann instead, before all
the others are included. This makes it available for all the checks.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
tests: Another client test

Test riemann_client_create() connecting against an unused port.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
event: Simplify riemann_event_create()

Do not NULL-check the return value of riemann_event_new(),
riemann_event_set_va() will do that for us anyway.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
docs/API.md: Correct an include path

It's <riemann/simple.h>, not <riemann-client/simple.h>.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
Release riemann-c-client 1.1.0

NEWS & configure.ac updated for the new version, and the library version
information was bumped in Makefile.am too.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>