#9 memory leaks, some other changes

Added boost for shared_ptr which is now used in
request_env and env_hash.
This was done to prevent memory leaks - pointers were
stored in vector but
they were not deleted anywhere.

Added test/env_hash for testing env_hash class. It uses
unit_test_framewor

Changed test/t/extra.conf.in - commented out
<Location />Order allow,deny...</Location> for httpd
which doesn't have
it compiled in.

Removed APR_BRIGADE_FOREACH from
example/output_filter/test_output.cpp,
it's missing in apr >= 1.2.0

[Anonymous]