Added comments

Change-Id: I11e5e3f4cc39538bb20065ddbd6a458dca3cf1d1
Improved theme styling

* Enabled wrapping for servermanager proxies page
* Made sure only depth 1 toctrees are rendered in the sidebar
* Added ParaView logo to sidebar
* Added Index link to the header
* Added current version under logo

Change-Id: I6de43b4d492009414996fa0d153a53108c52ae05
Improved section headings and toctree hierarchy

Change-Id: I45055f13403a35810f6162c5c7efd6fc51c516ee