Augmented .gitignore with suggested ignore for go
Moved to client, added Key.java to gitignore

Need to keep the key closed, sorry. You can probably guess its structure
from the usage, though :)
Added yaml descriptor of server app
Added .gitignore to shadow secret configuration
Added ISBN validation
Very basic WS
First working version
Removed debugging
Refactored to different packages, added cache

Caching only makes it sensible. Adding local storage next
Cache key generation made faster
Return only the info struct
Added datastore for book info
Added bookshelf data type
Minor refactorings