Updates the filters window to use a QSplitter layout for the properties area.
The handle is disabled for audio filter windows. The handle and property area are hidden when there are no filters.
Speeds up loading with large number of filters and prevents deadlock by
not getting the properties of filters during
OBSBasicFilters::UpdateFilters() which uses the source->filter_mutex
Code submissions have continually suffered from formatting
inconsistencies that constantly have to be addressed. Using
clang-format simplifies this by making code formatting more consistent,
and allows automation of the code formatting so that maintainers can
focus more on the code itself instead of code formatting.
The OBSBasicFilters window did not register a handler for the
"update_properties" signal. Now it does. Addresses issue #1028.
Closesjp9000/obs-studio#1036