(Following sentences are from README.)

Copyright (c) 2003-2008 Yusuke Kawasaki. All rights reserved.

Any commercial use of the Software requires a license directly from the
author(s). Please contact the author(s) to negotiate an appropriate
license. Commercial use includes integration of all or part of the
binary or source code covered by this permission notices into a product
for sale or license to third parties on your behalf, or distribution of
the binary or source code to third parties that need it to utilize a
product sold or licensed on your behalf.