It fully initializes the address structure, so no need for pre-initialization,
and also returns the length of the address, so no need to recalculate using
SOCKADDR_UN_LEN().
socklen_t is unsigned, so let's not use an int for it. (It doesn't matter, but
seems cleaner and more portable to not assume anything about the type.)
The enum used for column names is integer type while table_set_display() is parsing
arguments on size_t alignment which may result in assert in table_set_display() if
the size between types missmatch. This patch cast the enums to size_t.
It also fixes all other occurences for table_set_display() and
table_set_sort().
