macosx: remove the fullscreen button from the main window when running on Lion, since NSWindowFullScreenButton is present in the window title

It might not always be a bug.

 * Buffer push straight from input, no more repacketization.
 * Support for pause/resume.
 * Support for flush (and unused support for drain).
 * Larger buffers if available (as with HDA cards).
 * Reduced periods count to minimum (they are not normally required).

There should be more V4L2-based plugins later, e.g. FM RX, FM TX, VOUT.

The plugins cache now contains plugins file path relative to the base
plugins directory (the directory that contains plugins.dat). The cache
can hence be generated from a different absolute directory than the one
it is later installed to.

For native or emulated native builds, this enables build-time cache
generation.

Note however that the relative paths are different in the build tree
(modules/*/.libs/lib*_plugin.*) and in standard installation
(plugins/*/lib*_plugin.*). The cache cannot be copied from the build
tree to the installation directory.

This ensures that the vlc_entry__main prototype matches.

This is more flexible and extensible.

This avoids going through the linked list of modules. This is fine so
long as the module structure is indeed not in the list.

This should ease later implementation of proper error handling.

Again, this should help fix leaks in error paths.