Add coverage configuration for Distil

1. Add .coveragerc
2. Add coverage related files into .gitignore

Change-Id: I45a8cabb296595f42fe47fafddbd2fd56c132eb8

.coveragerc

@@ -0,0 +1,18 @@
+[run]
+branch = True
+source = distil
+omit =
+ .tox/*
+ distil/tests/*
+ distil/api/web.py
+ distil/auth.py
+ distil/database.py
+ distil/helpers.py
+ distil/initdb.py
+ distil/interface.py
+ distil/NoPickle.py
+ distil/rates.py
+ distil/transformers.py
+
+[report]
+ignore_errors = True

.gitignore

@@ -42,5 +42,9 @@ bin/waitress-serve
 local/
 test_vm/
 env/
+AUTHORS
 ChangeLog
 .idea
+
+.coverage
+cover/*