Adding begin/endTimeRange generation and parsing.
Renaming TimeRangePainter to TimePainter to make things less confusing.
Making painter calls take a rect bounds and adding input modifiers.
This enables click-to-select frames and marks.
Adding appendFlowData.
Adding EventFlag to the trace shim.
Computing time range levels.
Limit the events written to snapshots to only those used in the session.
Events created after the session starts are always written in.
Sharing range rendering code between zone/mark/timerange painters.
Adding time range painting/hit testing/etc.
Also moving tooltip argument generation to util for now.