Upstream PyQwt had effectively been unmaintained since 2009
Last release (v5.2.0) is from 2009. Its original author, Gerard Vermeulen,
publicly discouraged its use and recommended PyQtGraph on the mailing list
(http://sourceforge.net/p/pyqwt/mailman/message/30507558/) in Feb 2013.
There has been a revival attempt in Dec 2014: https://github.com/PyQwt, but
until today none of the repositories hosted under PyQwt GitHub organization has
received any commits/activity ever.