PerlInterpScope removed, the compatibility with threaded MPMs fixed

Hi,

as discussed in the thread about commit r1676417, I've removed 
PerlInterpScope directive. The reasoning is described in the 
http://svn.apache.org/r1682369 commit message, but I will paste it here too:

~~~
Remove PerlInterpScope directive as discussed on mailing list.
PerlInterpScope did not work correctly with httpd-2.4.x threaded MPMs.
For example when using 'PerlInterpScope connection' and multiple
requests are handled using the single connection, every request tries
to fetch new interpreter. This leads to deadlock soon, because we can 
always have more requests than interpreters.

There are more situations like the one described above and the fix is 
quite hard with the way how the usage of PerlInterpeters is designed 
currently.
~~~

This and other changes I've done in trunk today should fix the 
modperl-2.0.9-RC1 freeze seen with threaded MPMs on httpd-2.4.x. Could 
you please test it?

If things will look OK, maybe we could release RC2 to let more people to 
test it.

Regards,
Jan Kaluza