[Rivet] installation

[Frank Siegert]

Hi Andy and David,

> As Frank S just made clear, the big problem seems to be for people who
> want to install the development trunk in order to get new, _unreleased_
> analyses. I didn't even know that people were doing that: the
> experimenters I'm in touch with certainly aren't. It reopens (difficult)
> questions about whether we can make analysis releases more timely, but I
> think you need to appreciate that building an unreleased Rivet branch
> from version control isn't something that we advise anyone to do,

But we used to be advising this and supported it in the bootstrap script.

> nor
> has any particular effort been spent on making it easy. It specifically
> requires several non-trivial developer tools which aren't needed at all
> for the releases, so for people who take the "standard route" to use
> Rivet the issue never arises. Apologies for any "touch luck" subtext
> that made it into my reply, but that's a bit like me checking out the
> Sherpa 2 trunk a year ago and then complaining to you that your
> development code is unstable and unprofessional!

No, that comparison is flawed, because Sherpa does not get
contributions from the outside and has thus some responsibility of
making them available in a timely manner.

I still think that the development trunk usage is Ok (until we come up
with a code/analyses separation, which I don't see as feasible). This
comes with limited support of course, but at least it shouldn't be
made harder than necessary. And the switch from rivet-bootstrap ->
rivet-[12]-bootstrap must have made that impression on users.

Cheers,
Frank