Add option to empty bucket on deployment

[aslafy-z]

I would use an option that force emptying the bucket at deploy time.

[cklam2]

Yeah that would be very useful feature.
In our case we need it during an "upgrade" in the case that the bucket has received a new bucket name. So during the upgrade the stack should be able to remove the original bucket and it can only do that when it's empty.

[coyoteecd]

@aslafy-z Due to lack of response from project author, I reimplemented this plugin and published it to npm, including the option you were asking for, see my comments in #22.