xml: properly escape output
xml: add option to constrain max loglevel of recorded events
muxml: omit message-source div entirely if file/line number isn't known
muxml: fix wacky indentation in xsl file
test: fix clang warnings
Fix const-correctness and clang warning in logging path
Fix various valgrind warnings
Change how debug mode works

Make debug mode take the normal test code path with a special
option set in the loader.  This makes logging, iteration, and
timeouts work in this mode.
moonunit: add mode to list tests