HAL is officially deprecated. The new udev discs module provide the same
functionality in VLC. Moreover, the plugin was waking up the CPU at
regular intervals. Last, InitDeviceValues seemed to cause problems with
wrong disc paths being saved to vlcrc for some people

refs #3089

It should work with CDDA, DVD and Blu-rays, but I only tested DVD.

FIXME: This does not detect media change (eject/insert) properly yet.

This fixes my TV card, and should be backported after testing

and 4 is good as a default value)

Use a ToolButton+Menu since Qt4.6 on Windows seems to have fixed this issue.

So, it avoids the horrible size changes.

Btw, you really shouldn't use C cast on QObjects

Follows
http://cgit.freedesktop.org/libva/commit/?id=2822d025263d516bd619c8bbe1d17ff4c1bd1af2

This enables building avcodec plugin with VAAPI support.

make --disable-libgcrypt mandatory if (a recent enough) libgcrypt was not found

Product works for PCI as well, whereas model is only set for USB.

This implements device discovery with libudev, which is part of the udev
source package (and hence available in any recent Linux distribution).
Both cold and hot plugging (w.r.t. VLC) are implemented.

TODO:
 * V4L1 devices (currently V4L2 is assumed)
 * other subsystems (linux-dvb -> DVB, block -> discs)
 * item removal on unplug
 * better item name and category for non-USB devices