List view generation changed

*View generation code and hierachy simplified a bit.
*Got rid of the SqueezerIconicItemView, which has become unecessary since we now
 have the image cache.
*Introduced a new pending artwork icon.
*Added some more javadoc to the base classes in the Squeezer framework.
*Decreased the left padding in lists, to avoid inadvertently playing a song,
 when trying to hit the context menu.
*Slightly increased the size of the group views in the search result, to make it
 easier to use them.
Merge commit 'c41e5be0df7c2a3e10da4b01dcc932322562b7be' into actionbar

* commit 'c41e5be0df7c2a3e10da4b01dcc932322562b7be':
  List view generation changed

Conflicts:
	src/uk/org/ngo/squeezer/itemlists/SqueezerAlbumArtView.java
	src/uk/org/ngo/squeezer/itemlists/SqueezerPluginItemView.java
	src/uk/org/ngo/squeezer/itemlists/SqueezerPluginView.java