Combine uuid-old and uuid branch changes

- Switch to binary 16 for UUID keys
- Remove AccountScopedRecord base class, all model use binary uuids now
- Fix the search sql to serialize uuids properly
- Patch the MySQL schema dumper to output binary lengths

script/import-sqlite-database.rb

@@ -101,7 +101,7 @@ class Import
     end
 
     def generate_uuid
-      UuidPrimaryKey.generate
+      ActiveRecord::Type::Uuid.generate
     end
 
     def setup_account