[boost] New option for regression.py

Hello. I have done a patch for regression.py which adds a new option '--test-options'. I needed this to pass options to the actual test run. For example: python regression.py --toolset=tru64cxx65 --test-options='-sPYTHON_VERSION="2.3" -sPYTHON_ROOT="/opt" -sPYTHON_INCLUDES="/opt/include/python2.3 /opt/exec/OSF1-V5.1-alpha/include/python2.3"' Any interest in this? Markus