enhanced trace files

[typeholes]

More data is needed in trace files to enable better performance analysis. For starters, adding a timestamp to types.json lets us report types created during a timeframe and associate them with their checked expressions. implementation here https://github.com/typeholes/TypeScript/tree/trace-data

Options for execution:

1. Get a PR merged upstream into typescript. This is the preferred route.
2. Distribute a patched typescript with tracer. The obvious downside is only having a single ts version
3. Provide a code mod so users can build their preferred version with enhanced trace data
   a) possibly integrated into TS Version Switcher for ease of use.

[typeholes]

This is being addressed in the live-trace branch. No code mod will be needed