Study and respond to PyLint

Add a reasonably tolerant .pylintrc and fix most pylint errors and
warnings.

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.pylintrc

@@ -0,0 +1,20 @@
+[MASTER]
+init-hook="from pylint.config import find_pylintrc; import os, sys; sys.path.append(os.path.dirname(find_pylintrc()))"
+ignore-patterns=test_.*
+
+[MESSAGES CONTROL]
+
+# Pointless whinging
+#   R0201 = Method could be a function
+#   W0212 = Accessing protected attribute of client class
+#   W0613 = Unused argument
+#   C0301 = Line too long
+#   R0914 = Too many local variables
+#   C0111 = Missing docstring
+#   W1203 = Use lazy % formatting in logging functions
+
+# Disable the message(s) with the given id(s).
+disable=R0201,W0212,W0613,C0301,R0914,C0111,W1203
+
+[FORMAT]
+max-line-length=148