CodeQL tweaks and fixes.

Updated CodeQL config to ignore source templates,
because they are not syntactically valid source code.
Ignore other stuff that is irrelevant to published
code quality.

Made various fixes based on helpful CodeQL analysis.

source/python/setup.py

@@ -1,15 +1,19 @@
 from setuptools import setup
 
+def _LoadFile(filename):
+    with open(filename) as infile:
+        return infile.read()
+
 setup(
     name='astronomy-engine',
     version='2.1.8',
     description='Astronomy calculation for Sun, Moon, and planets.',
-    long_description=open('README.md').read(),
+    long_description=_LoadFile('README.md'),
     long_description_content_type='text/markdown',
     author='Donald Cross',
     author_email='cosinekitty@gmail.com',
     url='https://github.com/cosinekitty/astronomy',
-    license=open('LICENSE').read(),
+    license=_LoadFile('LICENSE'),
     classifiers=[
         "Intended Audience :: Science/Research",
         "License :: OSI Approved :: MIT License",