Expand toctree to three levels

Three levels makes it easier to find content in the
main toctree so lets make it easier for folks to use
the table of contents to find what they are looking for
instead of making it harder...

This change makes three levels look readable as well as
fixes some discrepancies among the various sections...

Change-Id: I5fd7a062adec052c338790c9ba343dfbc51075e3
Merge "Expand toctree to three levels"