(feature) Support overriding compilerOptions settings and tslint config

[LKay]

I would be very helpful if there was a way to override and extend the compilerOptions for typescript compiles and tslint options that are by default imported form tsconfig.json and tslint.json respectively.

This is especially useful for development only webpack configurations when in most cases there is no need for strict checking of some rules/flags such as noUnusedLocals for typescript or setting defaultSeverity for tslint.

[piotr-oles]

@LKay
Please try fork-ts-checker-webpack-plugin@alpha - I've published a new version which should resolve this issue 🚀
I will close this issue to clean-up the backlog. If this release didn't solve the issue, we can re-open this :)