New feature && Code Modification

[New Feature] Now bomb will zoom up and down before it explode
Bomb.js
1.Implementation of the new feature
Element.js
1.Comment add to illustrate the class
2.Define instance variables to the view's position _X, _Y
wsRequest....
1.suppress console.log
BM.js
1.implmentation of the new feature
BMM.js
1.BUG fix: BM will be appear in the grid.elementList correctly