CI/WIP: Use conda for most deps

closes #6870 

- [x] use conda.binstar.org/cpcloud channel for versions/packages not in conda defaults
- [x] possibly bring back the ccache, not totally sure what this is doing
- [ ] consider dropping python 3.2 support (I built py3.2.5 from source, I'll try to get it to work)
- [ ] update req files for numpy master

this doesn't remove maintenance, but it sure does simplify things, since conda recipes are very easy to create