[MERGE] Allows multiple '--starting-with' for selftest

[Andrew Bennetts]

Vincent Ladeuil wrote:
> 
> This patch allows selftest to recognize and handles multiple
> --starting-with options:
> 
>   bzr selftest -s bb.test_selftest -s bt.test_selftest
> 
> I filed bug #263249 along the way.

I like it.

bb:approve

-Andrew.