Gitignore maintenance

Change-Id: I4a27aceebbf5f0bf380220e81c1014bce7c7a5aa
diff --git a/.gitignore b/.gitignore
index dda5675..54c7891 100644
--- a/.gitignore
+++ b/.gitignore
@@ -34,6 +34,7 @@
 # Protobuf output files
 voltha/**/*.desc
 **/*_pb2.py
+**/*_pb2_grpc.py
 
 # Editors
 *.bak
@@ -41,3 +42,21 @@
 # Docker
 .docker-base-built
 
+# Mac stuff
+.DS_Store
+**/.DS_Store
+
+# Companion git repos used in tests
+loxigen
+mininet
+oftest
+olt-oftest
+pox
+openflow
+
+# Generated docs
+**/*.pdf
+docs/pon-requirements/*.svg
+
+# Files copied over during make
+ofagent/protos/third_party/google