Robot OS diagnostic_aggregator tools

 The diagnostic_aggregator contains a ROS node, aggregator_node, that listens
 to diagnostic_msgs/DiagnosticArray messages on the /diagnostics topic,
 processes and categorizes the data, and republishes on /diagnostics_agg. The
 aggregator_node loads "Analyzer" plugins to perform the diagnostics processing
 and categorization. The configuration and setup for each diagnostic aggregator
 is specific to each robot and can be determined by users or developers.
 .
 This package contains the tools.