Implemented a new "TimeStamp" struct for time keeping.
Merge branch 'Concurrent' into TimeStamp
Replaced "long" with "TimeStamp" struct that carries "TickCount"
Implemented "TimeStamp.Equals/GetHashCode" methods, updated test cases.
Merge branch 'Concurrent' into TimeStamp
Merge branch 'Concurrent' into TimeStamp
Moved "TimeStamp" class into a new file "TimeStampGenerator.cs"
Merge branch 'TimeStamp' into Concurrent
Moved test elsewhere and removed file "TimeStampOrderingTests.cs"
Merge branch 'master' of https://github.com/DynamoDS/Dynamo into Concurrent
Merge pull request #2170 from Benglin/Concurrent

Updated TimeStamp implementation