rqt_graph: add missing run_dependency on rosgraph_msgs
rqt_graph: remove obsolete pass
rqt_graph: follow PEP8
rqt_graph: refactor interface of edge coloring

set edge color as color, not obscure "heat" parameter
rqt_graph: avoid try-except when querying multi-dim arrays
rqt_graph: adapt to changes in TopicStatistics message def
rqt_graph: remove "bond" as quiet_topic, reorder
rqt_graph: add support for "Nodes/Topics" mode