Don't allow setting of dbName
Don't allow setting of dbName

This removes the ability to have multiple stores in one db.

rubenstolk/IDBWrapper,rubenstolk/IDBWrapper,kilbot/IDBWrapper,jayfunk/IDBWrapper,jensarps/IDBWrapper,mizchi/idb-wrapper-promisify,safetychanger/IDBWrapper,GerHobbelt/IDBWrapper,jayfunk/IDBWrapper,jensarps/IDBWrapper,mizchi/idb-wrapper-promisify,safetychanger/IDBWrapper,kilbot/IDBWrapper