Fixes the following warning:

warning C4505: 'operator ==' : unreferenced local function has been
removed

This function actually is used despite this warning, so the only way to
get rid of the warning is to disable the warning itself in this
particular case.

Fixes the following warning of MSVC:

warning C4244: '=' : conversion from '__int64' to 'uint32_t', possible
loss of data

Allows changing item selection via list box or via preview window, and
keeps their selection status in sync with each other.

Currently supported settings:
- Resolution
- Frame rate
- Input format

Accessing objects inside obs_datas after obs_data_clear was called on the
parent obs_data causes a NULL dereference.

Reproduce with:
	obs_data_t *data = obs_data_create();
	obs_data_set_obj(data, "foo", NULL);
	obs_data_clear(data);
	obs_data_get_obj(data, "foo");

The unsupported part should basically be signaled via making that
value inaccessible

Not calling recv when data is received will accumulate data in the
internal recveive buffer until it's full, in which case is will stop
acknowledging.  This can lead to unjustified disconnections.

Removes unnecessary allocations for the os_event_* and os_sem_*
thread functions

This works around a crash in the "widget->clear()" call in
ClearListItems under the following circumstances:
- Create at least two scenes
- Create at least one source in both scenes
- Have at least one source selected in both scenes
- Set the same "Switch to scene" hotkey on both scenes
- Use "Switch to scene" hotkey

Reduced stack trace on my machine:
    frame #0: 0x00000001004bac2d QtWidgets`QWidget::show() + 93
    frame #1: 0x00000001006d32a2 QtWidgets`QAbstractItemView::updateEditorGeometries() + 690
    frame #2: 0x00000001006d36d7 QtWidgets`QAbstractItemView::updateGeometries() + 23
    frame #3: 0x00000001006f1ae6 QtWidgets`QListView::updateGeometries() + 438
    frame #4: 0x00000001006ccdce QtWidgets`QAbstractItemView::doItemsLayout() + 46
    frame #5: 0x00000001006f1916 QtWidgets`QListView::doItemsLayout() + 214
    frame #6: 0x00000001006f9cf3 QtWidgets`QListViewPrivate::rectForIndex(QModelIndex const&) const + 611
    frame #7: 0x00000001006eb48d QtWidgets`QListView::visualRect(QModelIndex const&) const + 29
    frame #8: 0x00000001006f1567 QtWidgets`QListView::visualRegionForSelection(QItemSelection const&) const + 1863
    frame #9: 0x00000001006d7ba9 QtWidgets`QAbstractItemView::selectionChanged(QItemSelection const&, QItemSelection const&) + 73
    frame #10: 0x00000001006f97d2 QtWidgets`QListView::selectionChanged(QItemSelection const&, QItemSelection const&) + 674
    frame #11: 0x00000001006d9b9e QtWidgets`QAbstractItemView::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) + 1246
    frame #12: 0x0000000102b10372 QtCore`QMetaObject::activate(QObject*, int, int, void**) + 2994
    frame #13: 0x0000000102aa001c QtCore`QItemSelectionModel::emitSelectionChanged(QItemSelection const&, QItemSelection const&) + 300
    frame #14: 0x0000000102a9fe6c QtCore`QItemSelectionModel::select(QItemSelection const&, QFlags<QItemSelectionModel::SelectionFlag>) + 748
    frame #15: 0x0000000102aa048b QtCore`QItemSelectionModel::clear() + 75
    frame #16: 0x000000010072e9d8 QtWidgets`QListWidget::clear() + 24
    frame #17: 0x000000010015759d obs`ClearListItems(widget=0x000000010683afa0) + 141 at item-widget-helpers.cpp:43
    frame #18: 0x000000010003424b obs`OBSBasic::UpdateSources(this=0x0000000105f5bf50, scene=(val = obs_scene * = 0x0000000110679440)), &(obs_scene_release)>) + 75 at window-basic-main.cpp:1254
    frame #19: 0x0000000100036a96 obs`OBSBasic::UpdateSceneSelection(this=0x0000000105f5bf50, source=<unavailable>), &(obs_source_release)>) + 422 at window-basic-main.cpp:1473
    frame #20: 0x0000000100175c48 obs`OBSBasic::qt_static_metacall(_o=0x0000000105f5bf50, _c=InvokeMetaMethod, _id=17, _a=0x00007fff5fbfb640) + 776 at moc_window-basic-main.cpp:494

This crash was reported at
https://obsproject.com/mantis/view.php?id=364

SetThreadExecutionState with ES_DISPLAY_REQUIRED has the same effect of preventing the screensaver from activating. Using SPI_SETSCREENSAVEACTIVE leaves the screensaver disabled system-wide if OBS crashes before it can re-enable it.

The 'stopping' variable is superfluous due to the fact that 'stop_event'
accomplishes essentially the same exact thing.

If there was an attempt to destroy the rtmp-stream output while it was
already connecting and stopping at the same time, it would try to join
with the stop thread rather than with the connect thread.  The connect
thread would then continue past destruction.

The code assumed that the service was valid when that may not be the
case by the time it gets to the code.

Sometimes stopping a connection can lock up due to data that still
remains to be sent, and this would lock up the thread requesting the
stop (typically the UI thread).  So instead of locking up the calling
thread, spawn a new thread specifically for stopping so the calling
thread can continue uninterrupted.  If the user attempts to reconnect,
it will wait for the stop thread to complete in the connect thread
before attempting to connect.