Block bombing anyone who is ignored

[dgw]

The current code allows bombing someone whose attempts to defuse the bomb would be ignored.

Possible fix: Move checks for whether the target nick can be bombed into a function that can handle all the regular expression nonsense in bot.config.core.nick_blocks.

Bonus points: Handle bot.config.core.host_blocks also. There doesn't seem to be a way of getting the host of the target easily, only the calling user (via trigger.host), but this is a nice stretch goal. Punted to separate issue, #13.

[dgw]

We'll leave this be some more. It's already been nearly five years, but now there's an idea for making it easier to implement.