#4153 [HHQ-4018] ScheduleThread improvements

[Hyperic Team]

http://jira.hyperic.com/browse/HHQ-4018
The ScheduleThread class within the agent is responsible for collecting scheduled metrics from the plugins and sending results back to the server.

This class is being re-written to support cleaner integration with the CollectorThread and support of MeasurementPlugin.getValues().