Add duplicate Ubercart 3 platform with testing profile to support migrations from older versions which used acquia profile.

The hardcoded in Provision old_short_name pairs will now just work: uberdrupal -> minimal (for Ubercart 2 to 3 major upgrades) and acquia -> testing (for minor Ubercart 3 to 3 upgrades). The only not supported, but with very limited chance to exist is Ubercart 3 which used standard profile -- in this case see this hint: https://drupal.org/comment/8256311#comment-8256311
Clean-up the INSTALL.txt a bit.
Do not force old_short_name in any profile file directly.
PHP: 5.2 should not have catch_workers_output enabled.
PHP: Smooth transition from /usr/local/bin/php52 to /opt/php52/bin/php if used.