Keepa

- added sendRequestWithRetry with custom timeouts
- added singleVariation to DealsRequest
- added primeExclCSV to Offer
- added buyBoxUsedHistory to Product
- added BUY_BOX_USED_SHIPPING and PRIME_EXCL to CsvType
- removed deprecated fields from ProductFinderRequest and added new ones
- added new fields to Seller
- added Buy Box Used related fields to Stats
- updated dependencies and removed incorrect javadoc.

- connection timeouts can now be set per request
- fixed bug in product analyzer
- added lowestRank field for categories
- added new filters for deal requests