Added support for Sectioned Lists

These names are a little off. createAdapator takes in an adaptor?

What should happen is initDataSource or render in ListComponent should call

List<T> getListItems(DataSource<T> source)

and call Adapter<T> createAdapators()

These methods are overriden by SectionListComponent and the rest remains the same 

getListItems() is the one that should create the groups and flatten them out.

createAdapter should create the SectionListAdapter and padd it bakc