Merge pull request #43 from otherWIP/development

modified dispatcher flush()
First Draft - Listener timestamp

Moved the time stamping out of the dispatchers into the listeners. This
allows custom listeners to be written to query serial devices or read
files and provide their own timestamp.
Merge pull request #44 from otherWIP/listener_timestamp

Listener timestamping
Merge pull request #1 from emonhub/development

Development