updated version to 6.2.1-alpha2
inventory update quantity and prices: fixed potential null reference exception on CA failure without any result data
Items service: added DoesSkuExistList support and pagination with parallelization of some requests to speed up operations
linq extensions: fixed pagination to correctly handle possible null from processor
item service: updated not to log all requests failed when skus are missing for DoesSkuExistList
Merge pull request #2 from slav/master

 pull request #2 from slav/master