Change current concept of evalutation_periods

* Change current Synaps concept of evaluation_periods from over-lapping
  moving-average-style windows to serial & disjoint time extents

* The null sample counts should be excised from the GetMetricStatistics
  response.

* Test cases are updated to use randomly generated alarm or metric names

* Flag name related to size of in-memory window was changed

* Default port number was changed (from 8773 to 8776)

Implements bp aws-concept-evaluation-periods

Fixes bug 1077042

refs #1908 (for Samsung SDS internal tracker)