make tcpserver test independent from the local DNS

previously, check_tcpserver could have failed for
a testing host DNS (mis)configuration.

Now, getaddrinfo() is stubbed, so the tests are independent
and encapsulated.
Compile src/ using -Wall.
early initialization of container attributes

otherwise logger_get() instead plugin_create
will not work as expected.
Merge branch 'develop' of github.com:rugginoso/rapp into feature/config
Fix warnings