Clean up and Bug Fixes

Fixes #38 (closed)

Further changes:

• Third party warnings are suppressed now as they just polluted the warning summary in pystencils.
• Removing the math optimisations as they are not used in pystencils. An Issue is created to reintroduce them again in a clean way in the future
• Removing the joblib workaround as joblib is a hard dependency of pystencils
• Fixing SymPy 1.9 as maximum version
• Removing sympy.multiply_elementwise due to https://github.com/sympy/sympy/issues/22353. A workaround with NumPy is introduced which seems to be way more robust because NumPy has a more static API
• Introducing more extra requires, which are needed to have all features of pystencils
• Minor cleanup of some test cases and the datahandling

setup.py

 import distutils
 import io
 import os
-import sys
 from contextlib import redirect_stdout
 from importlib import import_module
 
@@ -11,6 +10,7 @@ import versioneer
 
 try:
     import cython  # noqa
+
     USE_CYTHON = True
 except ImportError:
     USE_CYTHON = False
@@ -32,13 +32,13 @@ class SimpleTestRunner(distutils.cmd.Command):
     @staticmethod
     def _run_tests_in_module(test):
         """Short test runner function - to work also if py.test is not installed."""
-        test = 'pystencils_tests.' + test
+        test = f'pystencils_tests.{test}'
         mod, function_name = test.rsplit('.', 1)
         if isinstance(mod, str):
             mod = import_module(mod)
 
         func = getattr(mod, function_name)
-        print(f"   -> {function_name} in {mod.__name__}" )
+        print(f"   -> {function_name} in {mod.__name__}")
         with redirect_stdout(io.StringIO()):
             func()
 
@@ -76,7 +76,7 @@ def cython_extensions(*extensions):
 
 
 def get_cmdclass():
-    cmdclass={"quicktest": SimpleTestRunner}
+    cmdclass = {"quicktest": SimpleTestRunner}
     cmdclass.update(versioneer.get_cmdclass())
     return cmdclass