… returns "undefined" (keep compatibility) or "true".

Because IndexedDB is limited on filtering, I had to use iterate and manually check each item with custom filters.
But I still need to limit the quantity of records returned, so I don't iterate the whole store, I know that there is the param "limit" the problem is that IDBWrapper doesn't know how many records passed my filter.
To solve this, I changed the "onItem" function to return a boolean and increment "recordCount" only if it returns "undefined" (keep compatibility) or "true".

…n array of stores.

Creation of a class called "Store" which contains the specific attributes of a store.
Main class changed to receive the param dbName and an array of store params to create each store inside the DB.
With these changes the user is able to create one DB with multiple stores.
Tests changed to comply with the new behavior.