Add the ability to add a projection map to a specified uri

[wmbest2]

This will be helpful for table join URIs

possible solutions

... {
    DatabaseHelper.addProjection(mJoinUri, "table1.id", "table1.id");

    DatabaseHelper.addProjectionMap(mJoinUri, aMap);

    DatabaseHelper.addProjectionForTable(mJoinUri, "table1", "id", "columna", "columnb", ...);
}