Add environment variables to control Cython extension compilation.

PYGSTI_CYTHON_SKIP being defined will fully skip extension compilation.
PYGSTI_CYTHON_EXCLUDE_FAILURES will run cythonize with exclude_failures=True.
Also removes the unneeded setup.cfg,
and applies PYGSTI_CYTHON_SKIP to the "No Cython" GitHub Actions.

Author: sserita

Diff for: .github/workflows/reuseable-main.yml

@@ -69,7 +69,7 @@ jobs:
     - name: Install package (No Cython)
       if: ${{ inputs.use-cython != 'true' }}
       run: |
-        python -m pip install -e .[testing_no_cython]
+        PYGSTI_CYTHON_SKIP=1 python -m pip install -e .[testing_no_cython]
     - name: Lint with flake8 (Linux only)
       if: ${{ inputs.os == 'ubuntu-latest'}}
       run: |

Diff for: MANIFEST.in

@@ -1,6 +1,5 @@
 include README.md CONTRIBUTING.md LICENSE
 include pyproject.toml
-include install_locally.py
 include requirements.txt
 include optional-requirements.txt
 include jupyter_notebooks/START_HERE.ipynb

Diff for: pyproject.toml

@@ -41,13 +41,13 @@ keywords=[
 classifiers=[
     "Development Status :: 4 - Beta",
     "Intended Audience :: Science/Research",
-    "License :: OSI Approved :: Apache Software License",
     "Programming Language :: Python",
     "Topic :: Scientific/Engineering :: Physics",
     "Operating System :: Microsoft :: Windows",
     "Operating System :: MacOS :: MacOS X",
     "Operating System :: Unix"
 ]
+license = "Apache-2.0"
 
 [project.optional-dependencies]
 diamond_norm = [