Free-SA 2.0.0b4p8

Dear Free-SA Users, please test this and further 2.0.0 betas and provide your feedback at forums and support/bug/feature request sections. It is required because I would release 2.0.0 final version soon.

Changelog from 2.0.0b4p6 to 2.0.0b4p8:
* FR3137680 (w_log_operations.c)
Clear cache directory in case if no records were found and exit with good return code.
* FR2135539 (w_config.*, r_index.c, free-sa.conf*)
New option for calendar navigation menu has been added.