When generating code on windows, generated import paths uses Windows path separators

[mthurlin]

When generating code on Windows, import paths ends up with Windows path separators:
import * as com_foo_core_thrift from "./..\\..\\..\\..\\core\\thrift";.

This works in Windows, but breaks for anyone trying to run the code somewhere else.

If it was normalized to import * as com_foo_core_thrift from "./../../../../core/thrift"; it would work everywhere.

I guess this is the culprit:
https://github.com/creditkarma/thrift-typescript/blob/master/src/main/render/shared/includes.ts#L223-L231