squelcher: combined (OO programming) the squelcher with the modify bot

[aaronkaplan]

As discussed today, the squelcher could benefit from the modifier's generic modify.conf language.
Please combine the two bots by

1. generalizing the modify bot
2. inheritance from the modify bot and using the same config syntax

The idea is that if I know how to edit the modify bot, I want to also be able to change the squelcher easily. ==> principle of simplicity.

Open to better ideas of course, but please document and convince me.

This implies that the configuration looks the same