message: Performance tests instructions added to README.
diff: @@ -161,6 +161,44 @@ npx mocha-webdriver-runner http://localhost:8081/ --chrome
  npx mocha-webdriver-runner http://localhost:8081/ --headless-firefox
  ```
  +### Run performance tests in Node.js environment
  +
  +As for now, there is no baseline for performance tests results, so before examining performance one
  +have to establish baseline:
  +
  +Performance test steps
  +
  +1) Establish baseline results.
  +
  +```
  +$ git checkout master
  +PROFILEHELPER_COMMAND=baseline yarn performance-test-node # create baseline of measurements for your particular platform
  +```
  +
  +> Note, that performance test suite is very limited, so it is highly possible that you
  +> have to write new dedicated performance test for code that is about to be optimized.
  +> See `tests/performance` for examples.
  +
  +2) Go back to your branch, change stuff and
  +
  +3) Rerun tests with your changes
  +
  +```
  +yarn performance-test-node --grep lines # assuming you're playing with lines
  +```
  +
  +4) Examine output:
  +
  +```
  +...
  +
  +performance createLineGeometry segments=2
  + min=0.0014ms (-2.44% vs 0.0014ms) sum=999.16ms (0% vs 999.12ms) repeats=499568.00 (-6.47% vs 534131.00) throughput=499988.43/s (-6.47% vs 534600.13/s)
  + avg=0.002ms (6.92% vs 0.0019ms) med=0.0015ms (0.2% vs 0.0015ms) med95=0.0031ms (17.6% vs 0.0026ms)
  + gcTime=39.6195ms (-3.39% vs 41.011ms) sumNoGc=959.54ms (0.15% vs 958.11ms) throughputNoGc=520633.00/s (-6.61% vs 557461.83/s)
  +```
  +
  +
  ### Generate documentation
  Run:
  