start removing BBExpandedLanguageBlockImageView. create files for BBLanguageBlockView and BBLanguageBlockViewFactory
add block view xibs
restore drag and drop functionality using xibs for each block view
add Blob color palette to interface builder, clean-up code
add block parameter views
style if-then and if-then-else blocks
style more blocks
accessory block view populates name and thumbnail image from model
populate operator and reaction blocks based on model