[4.0] Bug fix at PlayAfter

[4.0] Bug fix at PlayAfter

Fix two major bugs

1) when elapsed time is bigger then remain delaytime.

 For example, when elapsed time is 0.016s and delaytime is 0.001s.
 Previous version just delete 0.001s, and do nothing
  --> Information of 0.015 seconds is missed

2) when speedfactor is negative.

 Previous version do something like, remain_delay -= elapstime * speedfactor;
 In this case, if speed factor is negative, remain_delay time will increase
 so unlimited loop was occured in this case

Change-Id: Ib59a276a14a513fd34b458156cb29a0250c8cc70
Signed-off-by: Eunki Hong <eunkiki.hong@samsung.com>