add configuration setting to allow additional script directories

[j0rdan76]

Put a line in the config for Terminus-Bot to look in for extra scripts.

[kabaka]

Should not be too difficult. Will just have to rework the concept of Bot::SCRIPTS_PATH to be more dynamic and use arrays instead.

[kabaka]

Actually, we will also need to figure out how to handle script naming.

Presently, file names are used for identifying scripts. Using multiple directories, we will either have duplicate script names, script names that include the name of the parent directory, or we can disallow duplicate names and fail on load attempts.

Or we could always keep the last winner, allowing overrides of bundled scripts without having to modify them. I think this is my favorite.

If nobody disagrees, it will be done like this.