UI: Add stats dialog

Shows performance stats, and streaming/recording stats, and helps warn
the user when they have less-than-optimal values with coloring on the
values (e.g. yellow when getting low on disk space, red when getting
really low)

UI/CMakeLists.txt

@@ -131,6 +131,7 @@ set(obs_SOURCES
 	obs-app.cpp
 	api-interface.cpp
 	window-basic-main.cpp
+	window-basic-stats.cpp
 	window-basic-filters.cpp
 	window-basic-settings.cpp
 	window-basic-interaction.cpp
@@ -179,6 +180,7 @@ set(obs_HEADERS
 	platform.hpp
 	window-main.hpp
 	window-basic-main.hpp
+	window-basic-stats.hpp
 	window-basic-filters.hpp
 	window-basic-settings.hpp
 	window-basic-interaction.hpp