Rename Provider to ScoresProvider; add implementation

This renames the Provider as ScoresProvider and
starts a simple implementation: specifically:

 - There is a MatrixCursor called mScores that
   gets some dummy data in onCreate()
 - query() returns mScores

MatrixCursor is a simple 2D table for storing data
and can be passed to anything asking for a Cursor.

This implements the ‘R’ in CRUD; the ‘CRD’ are not
supported.  The one question is whether getType()
needs an implementation; it returns null for now.
Modify ScoresProvider to use static field names
Offer the ScoresProvider in the MainActivity

Here is the key change: we give it an authority
name that is different from its class name. The
content provider from the library project should
be available to the main project under the name
‘Scores’.
Very simple use of the ‘Scores’ content provider

This simply dumps every row of the ScoresProvider
to the log—but it does so using the content name
‘com.example.android.tictactoe.Scores’.
Make ScoreProvider available in the RedScores project

This does the same as the previous two commits for
the RedActivity: makes the ScoresProvider available
under the name:
‘com.example.android.tictactoe.RedScores’.