Add ReportPosition to report logstream filename/byte position
Add ReportMsg for reporting from logstreamer plugin
Only numerically format dasher values with a known representation
Lock logstreamSet where necessary in logstreamer_input
Update CHANGES.txt with LogstreamInput reporting
Merge branch 'features/logstreamer-reports' of github.com:mattcottingham/heka into mattcottingham-features/logstreamer-reports

Conflicts:
	CHANGES.txt
Merge branch 'mattcottingham-features/logstreamer-reports' into dev