[MERGE] Add --debugflag/-E option to selftest.

[Michael Hudson]

Martin Pool wrote:
> Martin Pool has voted tweak.
> Status is now: Conditionally approved
> Comment:
> 
> +    * New ``--debugflag``/``-E`` option to ``bzr selftest`` for setting
> +      debug flags.  The ``-Dselftest_debug`` global option has been 
> replaced by
> +      the ``-E=allow_debug`` option for selftest. (Andrew Bennetts)
> +
> 
> s/setting debug flags/setting options for debugging tests, these are 
> complimentary to the -D options/

'complementary' i think :)

Cheers,
mwh