Utilities/Sphinx: Add option to build 'singlehtml' format

Add SPHINX_SINGLEHTML to enable the Sphinx 'singlehtml' builder.
Merge branch 'master' into doc-singlehtml

Resolve conflicts in Utilities/Sphinx/CMakeLists.txt by adding the help
options from both sides.
Restore --help-full option to output all help manuals

This option was removed during conversion to the reStructuredText
documentation.  Restore it.  Process documentation starting at
Help/index.rst so that all manuals are included in the output.
UseSWIG: Add support for Go and Lua
Merge topic 'doc-full-help'

478356e6 Restore --help-full option to output all help manuals
Merge topic 'doc-singlehtml'

aaa6c8a6 Merge branch 'master' into doc-singlehtml
faf291a9 Utilities/Sphinx: Add option to build 'singlehtml' format
Merge topic 'UseSWIG-go-support'

a3b1be5e UseSWIG: Add support for Go and Lua