handle file input upload

Allow user to upload with the <input type="file"> input select as well.
Also added token to the selector as well.
Support callback function

Added callback function through config that will be triggered after
uploader ajax is done. Also renamed 'data' to 'response'.
HSUploader-2: Firefox permission denied

Fixed "Error: Permission denied to access property '0'". Firefox has
trouble accessing the dataTransfer.files object with files[0]. This
could be a bug on the browser or a security feature to prevent direct
accessing.

Fixed by using a loop to access the FileList's iterator to retrieve the
file object.
Cleaned console.log message

Cleaned console.log messages
Merge pull request #3 from harriswong/master

HSUploader-2: Firefox Permission Denied error