[pkg] various fixes
- add missing files to MANIFEST
- exclude doc/changes from dh_installchangelogs (it's a directory, which
dh_installchangelogs doesn't expect)
- fix doc build in debian package
include *.pyinclude */*.pyrecursive-include data *.gif *.png *.ico *.css *.jsrecursive-include i18n *.porecursive-include wdoc *