Implemented user specific settings + setting to hide images by default.

The syntax for changing user settings (since we don't currently have a UI way of changing them) is:

/settings <targetSetting> <get/set> <newValue>

Not perfect but it works for now.  If you update a setting however, you MUST refresh Bunker since we can't send updates to "current".  Once that is fixed we shouldn't have to refresh anymore.

This does require knowledge of what the name of your setting you want to get or set is, but its a good stopgap while we don't have a UI.