Minor updates to DDL and Adding data.sql

data.sql contains static data to be inserted after the database is
created. for now it just contains some mocked up Box data
Creating a static class to hold constants

Constants is a static class used to hold out applications constants.
Moving LogTags enum into constants and deleting the enum class (makes
more sense to use constants honestly)
Adding DataURI class for creating URIs

Convenience class to make sure you are creating correct URI's to access
the DataProvider. Also ocmmitting minor tweaks to DataProvider and
DatabaseHelper (to reflect DDL changes)
Example of how to use CursorLoader and Adapter

The BoxListActivity now uses a CursorLoader to asynchronously load data
from our DataProvider and a SimpleCursorAdapter to map this data into
the BoxListFragment's ListView.