[dunecontrol,release] Strip definition of NOBLANK as it is not used any more.
[cmake,release] Remove dead code.
[cmake,bugfix] Fixes issues in dependency tracking.

In this patch we rename dune_process_depedency_tree to
dune_process_depedency_macros because it actually just
include the macros of all modules that we depend on.
I addition we fix a bug that resulted in not executing the module's
own macro if there was only one dependency and now always process
it here.
[cmake,bugfix] Mark version with a space if the dependency does not require a version.

If we do not do that the length of the list of modules and corresponding versions
will differ as empty values will be neglected when appending to a list