[CODE] Use exceptions when a plugin fails to start

[yammesicka]

I think it can fit better than the current (status, msg) format.

[agamm]

But I love go errors :(
Lol, can you show an example of why this will look nicer?
Now people will have to memorize the exceptions, no?

[agamm]

This need the high label if we are going to implement this. Because it will require changes in all plug-ins.