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.
CMake Nightly Date Stamp
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
cmDefinitions: Don't store parent lookups

When looking up scopes, it is faster to not store the lookup locally to
keep the maps smaller and avoid extra allocations and rebalancing.
cmDefinitions: Avoid a find-then-insert when setting variables

Searching the map is not necessary.
cmDefinitions: Use a hashmap for faster checks

The hash map is much faster at checking that the map won't have what
we're looking for so that we can just go to the parent scope instead.