Bump package compatibility to Python 3.4

For all the Python-3-compatible packages:

* dev-python/ipython-irc
* dev-python/ipythonblocks
* dev-python/wheel
* dev-util/update-copyright
* net-proxy/package-cache

I've installed all of these locally with 3.4, and they seem to work.

dev-python/ipythonblocks: Matt Davis' Python-teaching package