ooiion-1361 Platform Agent should transition child devices into autosample mode when it receives the start_autosample. Add ops in PlatformAgent consistent with pattern to allow start_autosample/stop_autosample to be recusive in the same way that other commands are propogatesd to child devices. Add test to verify that the child devices enter streaming mode then exit as expected.
Merge pull request #1447 from MauriceManning/1361_rebase2

ooiion-1361 Platform Agent should transition child devices into autosample mode