src 0.7

[src](http://www.catb.org/~esr/src/) is a simple revision control system “with a modern UI for single-file solo projects kept possibly more than one to a directory”. This is a new RCS-like by Eric S. Raymond, still in its early stage (first release less than a week ago).

It has been on [HN](https://news.ycombinator.com/item?id=8601727)’s homepage for a couple hours now.
I already reported the issue on their IRC chan but this patch replaces `python2` with `python`, which is ok on OSX and most Linux distributions because `python` is an alias for Python 2, but it’ll break `src` on some distributions like Arch Linux where `python` is an alias for Python 3 and `src` needs Python 2 for now.