Fixed spelling mistakes.  Fixes GH-1
Support for migrating data between different storage implementations
Replaced test images with public domain images
First half of unit test for data migration
getAllAttachments returns an empty array if there are no attachments
a rough test of the data migrations
Correctly reads and compares the attachment blobs in the migration test

not that the migration test is even 100% correct, but it gives me good
feelings that that code is being exercised.
Fixed up the data migration test.  Added a migrated promise.
Added a convenient way to check the available storage implementations
clears the data migration test database after running the test

This reveal some intereseting errors with the filesystemapi...

it seems like you can't read from one directory while you are deleting
a different directory???
Working data migrations and tests for migrations
Scoped the db metadata to the database name so we don't get MD clashes
Created min version
Merge branch 'master' into gh-pages
Update to new rev