Version bump to 0.9.0 and updating CHANGES.txt

Version bump to 0.8.0 and updating CHANGES.txt

Version bump to 0.7.0 and updating CHANGES.txt

Version bump to 0.6.0 and updating CHANGES.txt

Version bump to 0.5.2 and updating CHANGES.txt

Version bump to 0.5.2 and updating CHANGES.txt

Version bump to 0.5.1 and updating CHANGES.txt

Version bump to 0.5.0 and updating CHANGES.txt

Version bump to 0.4.8 and updating CHANGES.txt

Version bump to 0.4.7 and updating CHANGES.txt