[Issue]
  Text is not visible.

[Cause]
  Crash for accessing property of an undefined object at the ASHandlers.GetVariable().

[Fix]
  Fixed not to do that no more.
[Issue]
  Degradation caused by the prev commit ("[Issue] Two texts overlap in moving together.")

[Cause]
  When replacing a display object with another, the old object's matrix is forcibly applied.

[Fix]
  If the PlaceObject itself has a non-identity matrix, use it, otherwise use the old object's matrix.
Merge pull request #59 from kuu/master

Two bug fixes for text issues.