xlwt and xlrd added to Naaya as dependencies. No need to assert availability.

git-svn-id: https://svn.eionet.europa.eu/repositories/Naaya/trunk/eggs/naaya.content.talkback@20648 a0171fae-0946-0410-966d-b1775066cd26
CHANGELOG.rst

git-svn-id: https://svn.eionet.europa.eu/repositories/Naaya/trunk/eggs/naaya.content.talkback@20649 a0171fae-0946-0410-966d-b1775066cd26