Move to buildout2.
Removed python 2.5 from travis

buildout 2.0 barfs on python 2.5. Fine to remove, I think.
Removed 2.4/2.5 support from the classifiers
Noted that python 2.4/2.5 aren't supported anymore
Remove mention of 2.4 and 2.5 support.
Merge remote-tracking branch 'origin/master'