Log Message:
Changes 1.7:
 This is a bugfix release. A bug in the progress bar code, which
 caused arithmetic exceptions on some 64-bit architectures, has been
 fixed.

Changes 1.6:
 This release contains an algorithm improvement that leads to a
 speedup of 20-60% over previous versions of potrace. A new PDF
 backend was added, courtesy of Tor Andersson. An option --progress
 was added for displaying a progress bar. The Windows version of
 potrace now uses MinGW instead of Cygwin, eliminating the need to
 install a special DLL alongside the executable programs, and solving
 some problems with wildcards and executable PostScript files. Some
 spurious "premature end of file" messages were eliminated. The
 core functionality of potrace was separated into a library with a
 documented API, making it easier for developers to incorporate
 potrace into other GPL-licensed software.