Merged and pushed. The docs are also updated.

LGTM.

OK, I added the workaround to the tutorial. Now all that's missing is updating 
the build instructions in the Fast Downward wiki. Malte, can I go ahead and merge 
the code?

The current "fix" for this problem is to call "make clean" and then "make". The
problem is that object files are checked into the VAL repository, which prevents
re-compiling all files in a fresh clone of the repository when simply typing "make".

Thanks. Now the only thing that's holding this back is that the VAL github 
version doesn't compile on Ubuntu 16.04. Silvan agreed to look into this.

The script/code changes at bitbucket look fine.

Before we close this, we should update the documentation on how to compile the 
planner (moving flex and bison to VAL's requirements, etc.).

I created a pull request at 
https://bitbucket.org/jendrikseipp/downward/pull-requests/49
and deferred making VAL optional to issue654.

After some offline discussion we found that the new sites contain enough 
information for people who know what they're doing :), but 
http://www.fast-downward.org/ScriptUsage should be made more detailed and 
tailored explicitly for Basel people. Ideally, it should be a list of explicit 
commands with opinionated default paths.

I think it would be good to have something somewhere that is more specialized
for us, i.e., that can be executed out of the box on our grid (without sudo
rights). But I think the existing information is great for non-internal users,
and I think that's enough for now. We can add the other stuff some other time if
we feel like it.

rtfd.org is now functional again and the updated docs are online. The docs at  
https://lab.readthedocs.io/en/latest/downward.tutorial.html and 
http://www.fast-downward.org/ScriptUsage are terse, but together, I think they 
contain all the things you mention (except for setting up an LP solver). What do 
you think is missing or should be changed?

This is a good starting point, but I think we really need a *complete* quick set
up, including all steps from scratch submitting an experiment. For example,
something we can point people to who should run Fast Downward experiments with
lab as part of a workshop or course.

This includes cloning and building Fast Downward, cloning and building VAL,
cloning (and building?) lab, cloning the benchmarks, setting up an LP solver
(I'd be OK if this part were initially missing), setting up all paths etc.

I added some info to the wiki (mostly a link to the lab docs, which still have to 
be built by rtfd.org): 
http://www.fast-downward.org/ScriptUsage

As part of this/before we merge this, can we make sure we have a page that
explains all the steps to set up Fast Downward and run experiments on our grid
(incl. getting the benchmarks, lab and VAL)?

I know that so far we have something like this on the AI wiki, but I think it
would be better to migrate it to the Fast Downward page so that we can look it
up when we're not at the university, and so that we point our students to it.
(The AI wiki is only accessible for our group, and it requires being on the
university network.)

Now that VAL has its own repo at https://github.com/KCL-Planning/VAL, we'd like 
to remove our old copy of VAL from the Fast Downward repo. Of course, we will 
adapt the driver script and still validate plans with the new VAL version.