lib: More intuitive syntax for TCP flags matching.

lib: More intuitive syntax for TCP flags matching.

Allow TCP flags match specification with symbolic flag names.  TCP
flags are optionally specified as a string of flag names, each
preceded by '+' when the flag must be one, or '-' when the flag must
be zero.  Any flags not explicitly included are wildcarded.  The
existing hex syntax is still allowed, and is used in flow dumps when
all the flags are matched.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>