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/wheel: Remove variables from HOMEPAGE

To comply with the devmanual [1].  Thanks to Jeroen Roovers for
pointing this out [2].

[1]: http://devmanual.gentoo.org/ebuild-writing/variables/index.html
[2]: https://bugs.gentoo.org/show_bug.cgi?id=459804#c1

dev-python/wheel: Add a live ebuild for Python's wheel installer