Complete iPod collection rewrite (also supports iPad, iPhone)

This is a result of 3-month effort to make Amarok iPod-like device
support future-proof and less buggy by using more modern MemoryMeta
framework to manage tracks internally.

The new plugin still uses libgpod [1] to access the devices and
supports all devices supported by it. The newest models may need the
infamous libashab.so library.

FEATURES:
* Small configuration dialog for iPods that shows troubleshooting information
and allows to change iPod name.
* Improved usability of iPod playlists: iPod collection automatically transfers
tracks dropped to iPod playlists to iPod when it is needed.
* Tracks can now be transcoded when transferring them to iPod.

CHANGES:
* optional libgpod dependency raised to 0.8.2 to support newest iPods.
* Amarok now prevents accidental unmounting of iPods in (small) time-frames
when iTunes database on iPod is not yet updated.
* Amarok detects when iPod is to be ejected from system and gracefully
disconnects it when it occurs.
* Hitting the eject button on iPod collection ejects it also from the system.
* iPod collection now detects whether iPod is safe to write and marks iPod
as read-only if not. This prevents "iPod shows 0 tracks" problem.
* Correct progress bar advancement when transferring tracks to iPod.
* iPod Collection supports multiple simultaneous cancellable transfers.
* Improved dialog to initialize iPod.

BUGFIXES:
* Detection and elimination of stale and orphaned iPod tracks now works
correctly; users are notified about these when iPod is plugged in.
* iPod playlists now work correctly.
* Show correct error when transferring unsupported files to iPod.

[1] http://www.gtkpod.org/wiki/Libgpod







FIXED-IN: 2.6
DIGEST: Amarok's iPod support is completely rewritten fixing many bugs
and adding features