source builds.

* SIGUSR2 handler sends SIGHUP to logger
  (default extra/logger could already handle SIGHUP).
* Add some options to cmd-line (to override config's options).

Conflicts:
	doc/user/connectors.xml

Remove connector/python and connector/ruby since
these drivers are hosted separately now.
https://github.com/mailru/tarantool-python
https://github.com/mailru/tarantool-ruby

Nullify risky os.*  methods, as well as 'require', to prevent load
of potentially risky dynamic libraries (.so).

Add a small test.

CMAKE_LOCALSTATE_DIR options added. Configuration file search path is changed to
${CMAKE_SYSCONF_DIR}/tarantool.cfg.

The run test script was updated.