* remove paths that do not have the specified prefix
* flag deleted files (<path action="D"...>)
* look at more command line compatibility with cvs2cl (e.g. -r, --revisions, --show-dead, --no-wrap, --hide-filenames, --lines-modified)
* only group entries if --group-by-day is given
* support more xslt processors
* group changes per autor per day
* svn2rss?
* if an authors.xml file exists in the current directory automatically pick it up
* improve performance of processing authors.xml