bug fixed

[one]
  The value of fn and fn1 is not equivalent in the case of the following ie<9
  The code applicable to the case is corrected.
  ======
  var fn = function fn1 () { alert(fn === fn1) } // ie.<9 false

[unbind]
  1) i have modified to be ignored if you give a "non-existent callback" to "unbind"
  2) msie does not have a "Array.indexOf", i made it to the corresponding

[test:unbind]
  add: non-existent callback
Merge pull request #11 from nazomikan/patch-1

Modification of behavior when given a callback that does not exist in "unbind".
release v.0.4.1
more cleanup