Adding an EXTRA_INFO attribute to tor versions
Tor versions often contain information about the SCM commit they came from, for
instance...
0.2.3.16-alpha-dev (git-
8be6058d8f31e578)
This isn't part of the spec, which in turn choked stem when I tried to parse
those versions. Adding this in and better defining a couple other points...
- The STATUS_TAG should only contain non-whitespace. Otherwise... well, just
about *anything* could be a 'valid' status tag.
- The spec says that status tags should be "compared lexically". The ASCII
value of 'Z' is greater than 'A' so I guess this means that they're sorted in
a reverse alphabetical order. This seems weird, but clarifying it.