Ed Baunton authored Jul 27, 2018 and Tristan Van Berkom committed Aug 04, 2018

Fix small error in docs in relation to `get_variable` documentation.

element.py (docs): dashes not underscores for build and install root

See merge request !577

This is needed to build docs without installing BuildStream.

  o Added feature to allow running shell commands

  o Removed unused codepaths to launch bst commands through the script,
    this program is anyway only used to parse and run the session files.

  o Fixed previous patch to run BuildStream uninstalled with
    the subprocess module, as running it in the same interpretor
    causes a bunch of problems.

Since we added support for shell commands in bst2html, this can now be fixed.

This is a part of issue #553

Build documentation without installing

See merge request !605

This patch just displays a better message than the default stack trace
but dose not try to fix the problem. A further patch will be created but
it effects versioneer so may take longer to land as it may need to go
via versioneer mainline.

This has been done in a way that I hope might be able to be upstreamed
in to versioneer. This is not garanteed but it would be good if it
could be.