30000 feet checkpoint: Convert ItemPickerDataSource's 'items' property to 'getItems:(NSRange)range' and related changes, for the purpose of allowing lazy loading of items.
Set tabImage property storage attribute to 'strong'.
Set 'readonly' on itemImagesEnabled property.
Fix image handling, comment, formatting.
Cleanup sample data source implementations.
Support item descriptions.
Rename method, minor refactor.
Minor refactor of SampleMediaDataSource
Fix sorting when there are duplicate items, correctly set TableSectionHandler on self, add descriptions to SampleMediaDataSource for songs.
Some nib fixes.
SampleMediaDataSource: Only show item descriptions for top-level data sources.
Disable 'Autoshrink' on labels.
Move API classes into ItemPickerSource/API.
Make properties on ItemPickerContext 'readonly'.
Support some more non-ascii characters when building sections.
Update comments.
More customizable table view header.
Fix MPMediaDataSource.
Merge branch 'master' of github.com:simontoens/STItemPicker

Conflicts:
	STItemPicker/ItemPickerSource/ItemPickerViewController.m