Allow setting bib4txt logger level at command line with -L option.
Allow setting bib4txt logger level at command line with -L option.

git-svn-id: 1a8437052ff7ea136a0b3ae3f7c303f50b092191@46 4b3877a5-4c1d-0410-b779-7f4527a406ac

matthew-brett/bibstuff