bumped minimum supported Python version to 2.4
implemented support for property diffs (Tigris #383)
allow user-configurable cvsgraph display (Tigris #336)
allow rNNNN syntax for Subversion revision numbers (Tigris #441)
display revision numbers in CVS tag/branch selector (Tigris #546)
allow roots to have optional context (#58)
use a more secure temporary file generator (#159)
fix problems with make-database and special characters (#141, #182)
fix bogus default ci_when value in cvsdb (#200)
standalone query interface removed (#206)
GUI support (--gui) removed from standalone.py

security fix: escape subdir lastmod file name