Clean up MainActivity by factoring UI actions out into their own
functions.
Refactor bookmark list activity source to use setup* and do* methods.
More refactoring.
Switch to an action provider for the address bar.
Moved completely to an address bar in the action bar.
Tweaks to address action display.
Start roughing in infrastructure for filtering.
Successfully passing model entry to the FilterActivity.
Start implementing model support for filters.
Generalize the ListItemFilter<T> interface and the FilteredListItem<T>
class.
Filter info getting back to main activity (skipping filter activity for
now).  Something has broken with load from a bookmark or at startup --
need to fix.
Bookmarks work again.

Added filtering support to the data collection pager adapter, but it's
not working yet.
Simplistic filtering now works.  To do:

- provide a way to remove/edit filters (FilterActivity)
- provide a way to save and load filters
- show in the info bar that a filter is active
- update the info bar to show the filtered count right away
- apply filters automatically from the URL fragment identifier
Create Sloop-specific filter classes.
New filter classes.
Refactor packages in Sloop, to separate an Android-independent util
package.
Minor reorg of layouts.

Start an empty layout for a filter form field.
Use alternative layouts instead of code for different display sizes.
The breakpoint (for now) is 600dp.
Eliminate unneeded import.
Roughing in the filter UI.