Speed-up TS compile time

[zhenwenc]

After migrated from ATL to ts-loader, there are quite a few options to speed-up the TS compile time for better development experience, such as:

• Performing type checking in a separate process with fork-ts-checker-webpack-plugin.
  • Ensure issues described here are all fixed.
• Parallelising the transpiration with thread-loader.

However, before deciding to apply the above improvements, are they really necessary? Unfortunately, I don't have such a big project to test with.