Capture and automatically load dependencies in modulefiles

[terhorstd]

This is fixes #3, by injecting multiple prereq statements into the modulefile template during its instantiation.

Issues with the multi-line prereq replacement have presumably been solved.

• The mechanism to replace multi-line variables does not work in the "old bash" branch of the template instantiation.
• Ideally the planfile could list 'build-time only' dependencies that should not be explicitly required at run time (e.g. compilers). (should be done in separate PR)

[terhorstd]

duplicate of #1

[terhorstd]

Re-opening from here to remove feature branches from central repository.

[terhorstd]

There is also one new package "bats" which is used for testing (see #20 ). Though these are seemingly unrelated files the framework was essential to find the possible errors, so it ended up in this PR not the other. This also has the nice side effect that bats is already available when tests are added later.
The "activation" of this feature in all module files is also done in a more structured manner in #20.

[stinebuu]

Thanks @terhorstd! This works for me, but I had to load quite a lot of modules, including ones that are not necessary for running NEST, like Cmake etc. This is not a problem, but something we can work on I think.

When building NEST, I loaded 3 modules (including CMake), and some of these loaded modules behind the scenes. When I then did module load nest-simulator/2.20.1, I then had to load all the hidden ones, because they where detected before the modules I had loaded manually. Also, when loading NEST, I got a message saying Lmod has detected the following error: Cannot load module "nest-simulator/2.20.1/default". At least one of these module(s) must be loaded: and then one module. It would be nice if in the future all of the modules needed where listed at the same time.

[terhorstd]

Thanks for the review, @stinebuu !
Yes, currently there is no distinction between build-time and run-time dependencies. cmake is a very good example. Maybe we can add some information to the plan files that mask out build-time-only dependencies. I opened issue #21 for this.
Regarding the module loading, we can easily change prereq to module load, then it would automatically load dependent modules. I'll create a new PR for that, then we can decouple the discussion and look into it there. (-> #22)