Brings it closer to more serious actions (adding branching
and allowing for late binding)

Unfortunately this breaks old syntax of the simple action.
But because simple is a pedagogical example unlikely to be used
in production environments (i.e its role is to serve as an example
on how to write actions), then this is ok.

New syntax for simple has new keyword "sdata". Example usage is:

sudo tc actions add action simple sdata "foobar" index 1
or
tc filter add dev $DEV parent ffff: protocol ip prio 1 u32\
match ip dst 17.0.0.1/32 flowid 1:10 action simple sdata "foobar"
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>