docs: add hack back in to avoid creating a python module package in API docs,...

docs: add hack back in to avoid creating a python module package in API docs, switch to imgmath extension

doc/Makefile

 gstlal-modules :
 	# FIXME FIXME FIXME total hack to work around unique python packaging
-	#mv ../gstlal/python/__init__.py ../gstlal/python/__init__.py.bk
+	mv ../gstlal/python/__init__.py ../gstlal/python/__init__.py.bk
 	sphinx-apidoc -e -o source/gstlal/python-modules ../gstlal/python ../gstlal/python/misc.py ../gstlal/python/bottle.py ../gstlal/python/coherent_null.py ../gstlal/python/matplotlibhelper.py
-	#mv ../gstlal/python/__init__.py.bk ../gstlal/python/__init__.py
+	mv ../gstlal/python/__init__.py.bk ../gstlal/python/__init__.py
 	sed -i "1s/python/\`\`gstlal\`\`/" source/gstlal/python-modules/modules.rst
 
 gstlal-inspiral-modules :

doc/source/conf.py

@@ -44,7 +44,7 @@ extensions = [
     'sphinx.ext.intersphinx',
     'sphinx.ext.todo',
     'sphinx.ext.coverage',
-    'sphinx.ext.pngmath',
+    'sphinx.ext.imgmath',
     'sphinx.ext.ifconfig',
     'sphinx.ext.viewcode',
     'sphinx.ext.githubpages',
@@ -65,7 +65,7 @@ master_doc = 'index'
 # General information about the project.
 # FIXME get from autotools
 project = u'GstLAL'
-copyright = u'2018, GstLAL developers'
+copyright = u'2021, GstLAL developers'
 author = u'GstLAL developers'
 
 # The version info for the project you're documenting, acts as replacement for