Always include time.h in server.c.
premake: replace LO_SO_VERSION in config.h
Check whether -Qunused-arguments can be given to C++ compiler.
Update doxygen configuration for doxygen 1.8.5.

Changes made automatically by running `doxygen -u'.
Fix typo in lo_version() documentation.
Fix error in doxygen \file line in lo_serverthread.h.