* Consumer API - add interrupt_current_operation to allow interrupting (from a separate thread) long consumer operation
* Producer API - return original data in callback payload.
* Producer API - allow to set queue limits (number of pending requests and/or max memory), reject new requests if reached the limits
* building rpm, deb and exe packages for client libs
BREAKING CHANGES
* Consumer API - get_next_dataset, get_last_dataset, get_dataset_by_id return dictionary with 'id','expected_size','content' fields, not tuple (id,content) as before
* Consumer API - remove group_id argument from get_last/get_by_id/get_last_dataset/get_dataset_by_id functions
* Producer API - changed meaning of subsets (subset_id replaced with id_in_subset and this means now id of the image within a subset (e.g. module number for multi-module detector)), file_id is now a global id of a multi-set data (i.g. multi-image id)
BUG FIXES
* fix memory leak bug in Python consumer library (lead to problems when creating many consumer instances)
