build: disable documention on xapian for travis-ci. --disable-documentation passed to configure doesn't work and I have a crash in sphinx that prevents testing. Use -enable-documentation=no which appears to be how 1.4.14 expects it at least. no-github-ci to disable testing for github as this change affects travis only at this point. If it works, I'll disable doc build on github to to save cycles.

License
=======

Roundup is Free Software under the following license (from the file
COPYING.txt in the software distribution):

.. raw:: html

   <div class="file_insert">

.. include:: ../COPYING.txt

.. raw:: html

   </div>