After the commit 3491487c71 obs_frontend_get_streaming_output()
returns NULL if "Start Streaming" button not pressed yet. The code
would erroneously fail to update the recording/streaming status if
either one of them hadn't been activated yet.
Closesjp9000/obs-studio#999
When the statistics window starts up for the first time, it reset values
at that very moment so that stray lagged frames due to OBS' startup
wouldn't be displayed. However, that's really a bad place to reset
those values because the user could want to view the stats window after
a long stream, and having those values reset when he/she views the
window for the first time would sort of make the point of viewing your
stats moot.
Instead, reset the values only when applicable, such as after OBSInit or
when video is reset.
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)
