CaptureBar: Fix panel size.
Fix NukeDownstream() for EVR-CP and Sync Renderer.

This commit fixes #720, #1807, #2625, #3161
Capture: Set default output file
Capture: Open capture bar automatically
Hide the seekbar in capture mode since it can never be used.
DVB: Try to avoid dummy resize
Split PM_CAPTURE state into PM_ANALOG and PM_DIGITAL
DVB: Don't update stats when channel is not active.