input type=file may be dangerous

Current implementation of the extension of  /input type="file"/  (described here: https://github.com/rogerwang/node-webkit/wiki/File-dialogs) can be dangerous and it can raise several security issues. I suggest to complete rollback this extension and implement it by different way. 

My opinion is that file-dialogs extension is one of the worst feature. You should complette avoid it.

I also disabled emulation of user guestures. To give scripts ability to emulate the user is also huge security issue.