Using lua file to give configuration. Added function parse_conf_file for this purpose.

Added const specifier to some parameters : info, videos, if_name, central_host
Added debug flag to gcc.
Fixed call to lua_next on video table with bad index.
Added options help and test.
uavsrv_recover: changed error management for socket and bind. Moved close(fd) to be after do{}while().
Added example of lua conf file.
Deleted debug printf in main().