improved content about using nssm to set up Windows services
fix typo in 4.9.1 Separate Sessions
updated ch6 drop to mention the need to delete a file if using sqlite
More details to connection string for Google Cloud SQL.
Discussion of eventual consistency and migrations in GAE.
Clarified writable=False and assignments to form.vars.field
Merge pull request #57 from lucadealfaro/master

GAE Datastore discussion, writable=False in forms, GAE SQL connection string
Merge pull request #56 from timrichardson/update_or_insert

Update or insert: added text about using a query as the select condition (from newsgroup post)
indetantation fix
Merge remote-tracking branch 'upstream/master'
Spanish ch. 10 spell-checking