Extended logging, start of discovery-less program.

Events logged: "collection phase", "reading file", "generating and sending precomputed vector", "compute sends sum", "master waits for result".

Events descriptions:
 - "collection phase" - waiting for all workers to send partial results.
 - "reading file" - reading mmapped file.
 - "generating and sending precomputed vector" - how much time it takes to generate and send a vector. Might be a little off, because it can be not serialized and thus not forced to be computed. Should be investigated.
 - "compute sends sum" - compute process send a partial answer to a collector, forcing the sum to be computed and sent to collector.
 - "master waits for result" - the time needed to send list of PIds to collector and obtain result from collector.