Cmake now finds xlib.
Moved compiler param mods to after 3rd party searches.

This prevents gmock from using our warnings and bailing.
Sandbox now creates a simple x11 window.
sandbox: Esc now behaves as ctrl+q.
Added *.autosave to .gitignore.
sandbox: Bashed SubstructureNotifyMask.
Added vars for width and height.
sandbox: Width and height changes are now tracked.
sandbox: Main loop may now optionally not block.
sandbox: Moved where main window handle is reset.

It's now reset when we schedule the window for destruction, not when
we receive the notification that it's been destroyed.
sandbox: Changed when events are processed.

Previously, we only processed one event per loop iteration. Without
doing anything else, this is fine, but if we're going to do
something else that flushes every iter, this will probably get backed
up.

Instead, we process all available events as soon as any are available.
sandbox: Infinite random lines.
sandbox: Now uses double buffering.