Remove the file BookmarkGridPage, since a GridView will do just fine.
Now we specify a height and width for the bitmaps rather than adjusting
them for the screen size.  Also add the favicon and match the design
more closely for the Add option.  In BrowserActivity, match the size
of the saved screenshots to the desired size for the Bookmarks
Activity.  Also move the logic into its own method so it can be
called from multiple places (still called in only one at the moment).

This way the two different modes can share code and have
all the same behaviors (i.e. context menu options).

AndroidManifest.xml
Remove BookmarkGridPage, which is no longer an Activity.

bookmarks.xml
Add a menu option to switch between the different viewing modes.

strings.xml
Name for that menu option.

AddNewBookmark.java
Remove copyTo, which is not necessary.

BookmarkGridPage.java
Change to just be a GridView, with our desired settings, and
overriding onSizeChanged to size the thumbs appropriately.  Now its
constructor takes a BrowserBookmarksAdapter, which it uses instead
of its old private Adapter.

BrowserBookmarksAdapter.java
Now has two modes, so it can be used for both the bookmarks grid
and the list view.  Removed a bunch of obsolete code, which was
used for searching/sorting the bookmarks.

BrowserBookmarksPage.java
Now switches back and forth between using a GridView and a ListView.

Change the look of the text.  Use a blank white rectangle with
rounded corners for sites without a stored screenshot.  Also
begin work on using the favicon.

Not the final visual design, but allows dogfooders to create new
bookmarks.

The BrowserProvider now stores another blob
for a screenshot of the page.  If the current
page is a bookmark, store a screenshot.  When
viewing bookmarks, show a gridview of screenshots
of the bookmarks.

Requires a change to framework to add THUMBNAIL
to Browser.BookmarkColumns and to the HISTORY_PROJECTION