v0.3.8: migrated temp_context* helpers to ae.core, exit_error() to App.shutdown(), check_if() to App.chk(), and removed get_main_app() and MockedMainApp

M  .gitignore
M  .gitlab-ci.yml
M  CONTRIBUTING.rst
M  LICENSE.md
M  README.md
M  SECURITY.md
M  ae/shell.py
M  dev_requirements.txt
M  pyproject.toml
M  setup.py
M  tests/conftest.py
M  tests/requirements.txt
M  tests/test_shell.py