533 sy 554 writer auto file cutoff

[LeonLiur]

Added file size check in domain/writer Commit(): if the current file size is too big, writer will commit the current domain, and start a new domain in a different file. The current domain's end timestamp is temporarily used as the domain writer's start timestamp. Upon next unary/writer.Write()call, a Stamp call is made to change the start timestamp of both unary and domain writers to the first timestamp written in the next domain.

Breaking / changed behaviour: When writing with a preset end, if the last commit of a writer is one where a file change was done, the End timestamp of that domain is the actual end, instead of the preset end (this is because if we set it to the preset end, upon opening the new domain, we would get an overlap error). Is this important?