Cvsplot 1.6.4 released

Made the cvs log parser more flexible. It seems not all cvs logs have "state: Exp;", but sometimes have "state: Rel;" when a new file is added. Accepted patch from Era Eriksson which fixes this. This was initially detected when running cvsplot over spamassassin. Added the -linestyle argument, which generates plots using lines, rather than discrete points. For large-range plots, this can improve readability.