Make plugins overrideable

[saep]

If you include a list of plugins from a module and you want to configure one of the plugins differently or replace it with a different configuration, it is currently necessary to explicitly redefine the whole list. It is probably easier to use the last definition.

To implement this, it is necessary to identify plugins and only start the last definition of the plugin.

• add name :: String field to Plugin data type
• implement logic to take the newest definition (i.e. the last occurrence with the same name) when plugins are initialized/started

Possible negative side effects:

• Plugins which happen to have the same name cannot be started from the same process