ci: speed up code-coverage jobs

Plus some documentation updates

Change-Id: I6fd2b04e22bca6c3d6e36e78d1995220e261206b
Refs: #3809
diff --git a/.gitignore b/.gitignore
index 10263e6..677f5ef 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,7 +1,7 @@
 # Emacs temp files
 *~
 
-# Mac OSX
+# macOS stuff
 .DS_*
 
 # waf build system
@@ -12,6 +12,7 @@
 
 # Compiled python code
 *.pyc
+*.pyo
 
 # Other
 VERSION