Various fixes before 3.0

- Fix .ini formatting issues in tox.ini file
- Updated developer docs regarding testing
- Add missing requirements for xosapi
- Fix typo in docs

Change-Id: I3603bbd68c8ecff68d8bbc1a2d4674908c54e5b9
diff --git a/containers/chameleon/Dockerfile.chameleon b/containers/chameleon/Dockerfile.chameleon
index b18ec5c..2b218e4 100644
--- a/containers/chameleon/Dockerfile.chameleon
+++ b/containers/chameleon/Dockerfile.chameleon
@@ -13,7 +13,7 @@
 # limitations under the License.
 
 # xosproject/chameleon
-FROM xosproject/xos-base:2.2.17
+FROM xosproject/xos-base:2.2.18
 
 # xos-base already has protoc and dependencies installed